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CBSE Solutions for Class 10 English

GSEB std 10 science solution for Gujarati check Subject Chapters Wise::

Choosing only words from the following list, write down the appropriate words to fill in the blanks from (i) to (vi) given below.

Addition, carbohydrates, CnH2n-2, CnH2n, CnH2n+2, electrochemical, homologous, hydrocarbons, saturated substitution, unsaturated, methane, nickel.
The alkanes form a (i) ………….. series with the general formula (ii) ………….. The alkanes are (iii) ………….. (iv) ………….. which generally undergo (v) ………….. reactions. First homologue of this series is named as ………….. (vi).

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જવાબ : (i) homologous
(ii) CnH2n+2
(iii) saturated
(iv) hydrocarbons
(v) substitution
(vi) methane


Give One word Answers for the following :- A gas prepared when ethyl alcohol is treated with concentrated sulphuric acid.

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જવાબ : Ethene


Give One word Answers for the following :- Ethyl alcohol containing methanol is known as

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જવાબ : Spurious liquor


Give One word Answers for the following :- The process of removal of water from organic compounds.

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જવાબ : Dehydration


Give One word Answers for the following :- The process by which hydrogen converts unsaturated compounds to saturated compounds.

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જવાબ : Hydrogenation


Give One word Answers for the following :- The process by which bigger hydrocarbons split into smaller hydrocarbons.

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જવાબ : Pyrolysis


Give One word Answers for the following :- Organic acid present in vinegar.

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જવાબ : Acetic acid


Give One word Answers for the following :- A solution used to store biological specimen.

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જવાબ : Formalin


Give One word Answers for the following :- A gas used for artificial ripening of fruits.

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જવાબ : Ethene / Ethyne


Give One word Answers for the following :- A reagent which can be used to distinguish between ethene and ethyne.

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જવાબ : Ammoniacal cuprous chloride


Give One word Answers for the following :- A white solid which on treatment with water liberates acetylene.

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જવાબ : Calcium carbide


Give One word Answers for the following :- The category of compounds with OH as functional group.

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જવાબ : Alcohol


Give One word Answers for the following :- The category of compounds with -COOH as functional groups.

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જવાબ : Carboxylic acid


Give One word Answers for the following :- Used for making pickles and preservatives.

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જવાબ : Vinegar


Give One word Answers for the following :- Catalyst used to convert alkanes to aldehydes.

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જવાબ : Molybdenum oxide


Give One word Answers for the following :- A gas which is also known as marsh gas.

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જવાબ : Methane


What do you understand by oxidizing agents?

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જવાબ : Oxidizing agents are the substances which give oxygen to another substances or which remove hydrogen from a substance.
For example, acidic K2Cr2O7 is an oxidizing agent that converts (oxidizes) ethanol into ethanoic acid.


Why are carbon and its compounds used as fuels for most applications?

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જવાબ : Carbon and its compounds are used as fuels for most of the applications because they burn in air releasing a lot of heat energy.


Why is the conversion of ethanol to Ethanoic acid an oxidation reaction?

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જવાબ : The conversion of ethanol into ethanoic acid is called an oxidation reaction because oxygen is added to it during this conversion


What would be the electron dot structure of a molecule of sulphur, which is made up of eight atoms of sulphur? (Hint – The eight atoms of sulphur are joined together in the form of a ring.)

 

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જવાબ : NCERT Solutions for Class 10 Science Chapter 4 Carbon and its Compounds Q2


What would be the electron dot structure of carbon dioxide which has the formula CO2?
 

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જવાબ : NCERT Solutions for Class 10 Science Chapter 4 Carbon and its Compounds Q1


Which of the following hydrocarbons undergo addition reactions :
C2H6, C3H8, C3H6, C2H2 and CH4
 

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જવાબ : Addition reactions take place only in unsaturated hydrocarbons. So addition reaction take place only in C3H6 and C2H2.


What is hydrogenation ? What is its industrial application ?

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જવાબ : The addition of hydrogen to an unsaturated hydrocarbon to obtain a saturated hydro-carbon is called hydrogenation. The process of hydrogenation takes place in the presence of nickel (Ni) or palladium (Pd) metals as catalyst.
NCERT Solutions for Class 10 Science Chapter 4 Textbook Chapter End Questions Q12
Application : The process of hydrogenation has an important industrial application. It is used to prepare vegetable ghee (or vanaspati ghee) from vegetable oils.


What change will you observe if you test soap with litmus paper (red and blue)?

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જવાબ : Red litmus will turn blue because soap is alkaline in nature. Blue litmus remains blue in soap solution.


Explain the formation of scum when hard water is treated with soap.

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જવાબ : Hard water contains salts of calcium and magnesium. Calcium and magnesium on reacting with soap form insoluble precipitate called scum. The scum formation lessens the cleansing property of soaps in hard water.


Why are carbon and its compounds used as fuels for most applications ?

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જવાબ : Carbon and its compounds give a large amount of heat per unit weight and are therefore, used as fuels for most applications.


Why does micelle formation take place when soap is added to water ? Will a micell be formed in other solvents such as ethanol also ?

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જવાબ : Micelle formation takes place when soap is added to water because the hydrocarbon chains of soap molecules are hydrophobic (water repelling) which are insoluble in water, but the ionic ends of soap molecules are hydrophilic (water attracting) and hence soluble in water.
Such micelle formation will not be possible in other solvents like ethanol in which sodium salt of fatty acids do not dissolve.


What are homologous series? Explain with an example.

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જવાબ : Homologous series : A homologous series is a group of organic compounds having similar structures and similar chemical properties in which the successive compounds differ by -CH2 group.


People use a variety of methods to wash clothes. Usually after adding the soap, they ‘beat’ the clothes on a stone, or beat it with a paddle, scrub with a brush or the mixture is agitated in a washing machine. Why is agitation necessary to get clean clothes?

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જવાબ : It is necessary to agitate to get clean clothes because the soap micelles which entrap oily or greasy particles on the surface of dirty cloth have to be removed from its surface. When the cloth wetted in soap solution is agitated or beaten, the micelles containing oily or greasy dirt get removed from the surface of dirty cloth and go into water and the dirty cloth gets cleaned.


Would you be able to check if water is hard by using a detergent?

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જવાબ : No, because detergents can lather well even in hard water. They do not form insoluble calcium or magnesium salts (scum). On reacting with the calcium ions and magnesium ions present in the hard water.


The formula of a hydrocarbon is CnH2n. Name the family to which it belongs and also predict its nature.

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જવાબ : The hydrocarbon belongs to alkene family. It is unsaturated in nature.


Why is candle flame generally yellow ?

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જવાબ : Candle flame is generally yellow due to the presence of unburnt carbon particles. When light falls on these particles, they scatter yellow colour. This shows that the combustion of hydrocarbons present in wax or candle is not complete.


Out of ketonic and aldehydic groups, which is the terminal functional group ?

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જવાબ : Aldehydic group
Previous Year Question Papers for CBSE Class 10 Science Chapter 4 Carbon and Its Compounds 1


A family of organic compounds has the functional group ‘al’. What is its name ?

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જવાબ : The family is of aldehydes also called alkanals.


Which is common in all the members of a family ?

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જવાબ : They have the common functional group.


Why are organic compounds present in such a large number ?

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જવાબ : This is due to the self linking property of carbon known as catenation.


What is the valency of carbon in its compounds ?

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જવાબ : Carbon is tetravalent in its compounds.


What are the essential constituents of all organic compounds ?

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જવાબ : Carbon and hydrogen are the essential constituents of all organic compounds. However, carbon tetrachloride (CCl4) is an exception.


What is hydrogenation? What is its industrial application?

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જવાબ : It is a class of chemical reactions in which the net result is addition of hydrogen (H2) to unsaturated organic compounds such as alkenes, alkynes, etc. Hydrogenation is widely applied to the processing of vegetable oils and fats. Complete hydrogenation converts unsaturated fatty acids to saturated ones.


What change will you observe if you test soap with litmus paper (red and blue)?
 

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જવાબ : Soap is the salt of a strong base (NaOH) and a weak acid (carboxylic acid), so a solution of soap in water is basic in nature. Being basic, a soap solution turns red litmus paper blue.


Name the functional group present in the compound CH3CH2CH2COOH.
 

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જવાબ : The functional group (—COOH) is known as carboxyl group.


Write the molecular formula of the first two members of the homologous series having functional group >C=0. (CBSE 2017)

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જવાબ : Previous Year Question Papers for CBSE Class 10 Science Chapter 4 Carbon and Its Compounds 2


What is common in the structures of the compounds methonal and ethanol ?

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જવાબ : They have the same functional group (—OH) known as alcoholic group.


A compound with molecular forumla C2H6O is used as a fuel. Identify the compound.
 

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જવાબ : The compound is ethanol with formula C2H5OH.


The molecular formula of butane is C4H10. What is the formula of butene ?

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જવાબ : The formula of butene is C4H8.


Which has a triple bond; C2H2, C3H4 and ?

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જવાબ : C3H4 has triple bond with the formula CH3C ≡ CH


Which of the following belong to the same homologous series ?
C3H8, C4H8, C4H6, C3H6.
 

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જવાબ : C3H6 and C4H8 belong to the same homologous series which is alkenes with general formula CnH2n.


Write IUPAC and common names of CH3COCH3, C2H5COOH.

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જવાબ : CH3COCH3 : Propanone, Acetone
C2H5COOH : Propanoic acid, Propionic acid.


What is the role of soap in cleansing of clothes ?

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જવાબ : Soap helps in forming a stable emulsion between oil drops carrying dirt particles and water. The emulsion is also known as micelle.


Name the second member of alkyne family. Give its structure.
 

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જવાબ : The second member of alkyne family is propyne. Its structural formula is H3C—C = CH.


What do we get when ethanoic acid reacts with ethanol in the presence of concentrated sulphuric acid ?

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જવાબ : Ethyl ethanoate (CH3COOC2H5) is formed by esterification reaction. It has fruity smell.


An unknown compound has the smell of vinegar. Identify it.
 

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જવાબ : The compound is ethanoic acid also called acetic acid.


When do you get yellow soot in the burner flame ?
 

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જવાબ : Yellow soot is obtained when the holes of the burner are not clean. The combustion is incomplete. The yellow – soot or yellow flame is because of unburnt carbon particles.


Can you check hard water by using a detergent ?

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જવાબ : No, it is not possible because detergents give lather with both soft and hard waters.


Which organic compound is added to make ethanol unfit for drinking purposes ? What is the name of the mixture formed ?

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જવાબ : Methanol which is highly poisonous is added in small amount to ethanol in order to make it unfit for drinking purposes. The mixture is called methylated spirit or denatured alcohol.


Out of butter and ground nut oil, which is unsaturated in nature ?
 

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જવાબ : Ground nut oil is unsaturated in nature.


Give a test to identify the presence of ethanoic acid.
 

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જવાબ : Dip a strip of blue litmus paper in the solution of ethanoic acid. Its colour will change to red.


Vapours of a hydrocarbon were passed through bromine dissolved in carbon tetrachloride. The yellow colour of bromine got discharged ? Predict the nature of the hydrocarbon.

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જવાબ : The hydrocarbon is unsaturated. It is either an alkene or alkyne.


Select the saturated hydrocarbons from the following
C3H6; C5H10; C4H10; C6H14; C2H4 (CBSE 2016)

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જવાબ : The compounds C4H10 (butane) and C6H14 (hexane) are saturated hydrocarbons. They correspond to the molecular formula CnH2n+2.


Which element exhibits the property of catenation to maximum and why ? (CBSE 2016)

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જવાબ : The element is carbon. This is because of very small size of carbon atom (77 pm) and high strength of C—C bond (355 kj mol-1).


Identify from the following the hydrocarbons that undergo addition reactions :
C3H4, C2H6, CH4, C2H4. Justify your answer

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જવાબ : The hydrocarbons are C2H4 (ethene) with formula CnH2n and C3H4 (propyne) with formula CnH2n-2 both are unsaturated.


Which functional groups are present in the family of
(i) alcohols
(ii) aldehydes
(iii) carboxylic acids ?
 

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જવાબ : (i) —OH
(ii) —CHO
(iii) —COOH.


Ethanol is one of the most important industrial chemicals. It is used in medicine, to synthesise many important compounds and as an excellent solvent.
However, inspite of its benefits it causes many social problems. If a person drinks alcohol regularly, he becomes an alcoholic. Alcohol is non-toxic but it produces physiological effects disturbing brain activity. These persons are also a threat to the lives of others.
(a) Give three reasons in favour and three reasons against ‘alcohol-free world’.
(b) ‘Alcohol drinking should not be portrayed on media’. Give valid reasons to justify.
(c) As a student what initiative would you take in the concern of “We should condem drinking alcohol”,

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જવાબ : (a) In favour of‘Alcohol-free world’:

  • Alcohol drinking lowers inhibitions which leads to increased violence and crime in the society.
  • A liver disease ‘cirrhosis’ caused by alcohol can lead to death.
  • Drunken driving leads to increased road accidents.
Against ‘Alcohol-free world’:

  • Alcohol is used for making some medicines like cough syrups, tincture iodine, some tonics, etc.
  • Mixed with petrol, it is now being used as a fuel for light vehicles.
  • It is used for making antifreeze material for cooling engines of vehicles.
(b) ‘Alcohol drinking should not be portrayed on media’ because young people and children are greatly influenced by the media.

(c) Initiatives taken by a student to create awareness about drinking alcohol could be:

  • By writing slogan
  • Through debates
  • By writing articles
  • By role plays/skits


What are detergents chemically? List two merits and two demerits of using detergents for cleansing. State the reason for the suitability of detergents for washing, even in the case of water having calcium and magnesium ions.

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જવાબ : Detergents chemically are sodium or potassium salts of sulphonic acid of benzene or alkene.
Merits:
(i) They work well with hard water.
(ii) They are more effective than soaps.
Demerits:
(i) They are expensive.
(ii) Some of them having branching are non-biodegradable, therefore create water pollution.
Detergents are suitable for hard water having  Mg2+ and Ca2+ ions because they do not form insoluble salts with Mg2+ and Ca2+ ions.


What is the difference between the chemical composition of soaps and detergents? State in brief the action of soaps in removing an oily spot from a shirt. Why are soaps not considered suitable for washing where water is hard?

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જવાબ : oaps are sodium or potassium salts of fatty acids having — COONa group. Detergents are
sodium or potassium salts of sulphonic acids having — SO3Na and — SO4Na group. Cleansing action of soap: Soap molecules consist of a large hydrocarbon tail which is hydrophobic (water-hating or water repelling) with a negatively charged head which is hydrophilic (water-loving) as shown in figure.
carbon-and-its-compounds-chapter-wise-important-questions-class-10-science-40
When a soap is dissolved in water, the molecules associate together as clusters called micelles in which water molecules, being polar in nature, surround the ions and the hydrocarbon part of the molecule attracts grease, oil and dirt.


Define homologous series of organic compounds. List its two characteristics. Write the name and formula of the first member of the series of alkenes.

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જવાબ : The series of organic compounds having same functional group and similar chemical properties is called homologous series.
Each member differs from successive member by —CH2— group. The difference in molecular weight between two successive members is 14 u.
Characteristics:
(i) It has same general formula, from which, all members can be derived.
(ii) They have similar chemical properties.
C2H4, CH2=CH2, Ethene is first member of alkene series.


Give reasons for the following:
(i)Element carbon forms compounds mainly by covalent bonding.
(ii)Diamond has a high melting point.
(iii)Graphite is a good conductor of electricity.
(iv)Acetylene bums with a sooty flame.
(v)Kerosene does not decolourise bromine water while cooking oils do.

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જવાબ : (i) It is because carbon has four valence electrons, it cannot gain or lose four electrons because high energy is needed. It can only share four electrons.
(ii) It is due to strong covalent bonds and compact structure of diamond.
(iii) It is due to presence of free electrons in graphite because each carbon is linked to three more carbon atoms.
(iv) It is due to high percentage of carbon, it burns with sooty or smoky flame.
(v) Kerosene oil is mixture of saturated hydrocarbons therefore does not decolourise bromine water.


(a) State two properties of carbon which lead to a very large number of carbon compounds.
(b) Why does micelle formation take place when soap is added to water? Why are micelles not formed when soap is added to ethanol?

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જવાબ : (a) (i)-Catenation (ii) Tetravalency
(b) It is because large number of molecular ions of soaps get aggregated and form colloidal solution. Soap has hydrophobic tail (hydrocarbon) which dissolves in hydrocarbon part and hydrophilic part dissolves in water. Ethanol is non-polar solvent therefore micelles are not formed because hydrocarbon part gets attracted towards ethanol and ionic end will not dissolve in alcohol.


Name the functional group of organic compounds that can be hydrogenated. With the help of suitable example explain the process of hydrogenation mentioning the conditions of the reaction and any one change in physical property with the formation of the product. Name any one natural source of organic compounds that are hydrogenated.

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જવાબ : carbon-and-its-compounds-chapter-wise-important-questions-class-10-science-15
When unsaturated hydrocarbons are heated with hydrogen in the presence of nickel as catalyst, saturated hydrocarbons are formed. If the starting unsaturated hydrocarbons are liquids, they will change into solids. Vegetable oils are hydrogenated to form vegetable ghee. Plants are natural sources of vegetable oils which can be hydrogenated.


Give a test that can be used to differentiate between saturated and unsaturated hydrocarbons.

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જવાબ : Bromine water test – is used to differentiate between the unsaturated compounds (like alkenes and alkynes) and the saturated compounds. For this purpose, bromine is used in the form of bromine water. A solution of bromine in water is called bromine water. Bromine water has a red-brown color due to the presence of bromine in it. When bromine water is added to an unsaturated compound, then bromine gets added to the unsaturated compound and the red-brown color of bromine water is discharged. So, if an organic compound decolorizes bromine water, then it will be an unsaturated hydrocarbon (containing a double bond or a triple bond), but saturated hydrocarbon (alkanes) do not decolorize bromine water.

Bromine water test is perform to differentiate between the unsaturated compounds (like alkenes and alkynes) and the saturated compounds. Bromine water is added to an un-saturated hydrocarbon red brown color of bromine solution is discharged. Si if there is dis-coloration then the compound will be an unsaturated Hydrocarbon.


Why does micelle formation take place when soap is added to water? Will a micelle be formed in other solvents such as ethanol also?

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જવાબ : Micelle formation takes place because of the dirt particles in water and clean water. There are two mediums that are involved: one is pure water and the other being dirt (also called as impurities). The soap also has two mediums:

(i) organic tail and

(ii) ionic head

So the organic tail mixes and dissolves with the dirt whereas the oil or grease and ionic head dissolves and mixes with the water. Therefore, when the material to be cleaned is removed from the water, the dirt is taken off by the soap molecules in the water. Hence, the soap cleans by forming closed structures by the mutual repulsion of the micelles (positively charged heads).


Explain the nature of the covalent bond using the bond formation in CH3Cl

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જવાબ :  

Solution: Carbon can neither lose 4 electrons nor do gain four electrons as these process make the system unstable due to requirement of extra energy. Therefore CH3Cl completes its octet configuration by sharing its 4 electrons with carbon atoms or with atoms of other elements. Hence the bonding that exists in CH3Cl is a covalent bonding.

Here, carbon requires 4 electrons to complete its octet, while each hydrogen atom requires one electron to complete its duplet. Also, chlorine requires an electron to complete the octet. Therefore, all of these share the electrons and as a result, carbon forms 3 bonds with hydrogen and one with chlorine.


Two carbon compounds ‘A’ and ‘B’ have the molecular formula C3H8 and C3H6 respectively. Which one of the two is most likely to show addition reactions ? Justify your answer. Explain with the help of a chemical equation, how an addition reaction is useful in vegetable ghee industry.

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જવાબ : The compound ‘A’ with formula C3H8(propane) is a saturated hydrocarbon and corresponds to general formula CnH2n+2. The compound ‘B’ with formula C3H6 (propene) is an unsaturated hydrocarbon and corresponds to general formula CnH2n. It has a double bond (C=C) and is therefore, unsaturated.
Previous Year Question Papers for CBSE Class 10 Science Chapter 4 Carbon and Its Compounds 33
The compound ‘B’ will take part in the addition reactions. As a result, double bond will change to single bond. For example,
Previous Year Question Papers for CBSE Class 10 Science Chapter 4 Carbon and Its Compounds 34
The addition reaction is quite useful in the hydrogenation of oils i.e., to convert edible oils like ground nut oil and cotton seed oil which are unsaturated in nature into solid fats which are of saturated nature.


(a) How are carboxylic acids different from mineral acids from ionization point of view ?
(b) Describe an activity to show how ethanoic acid reacts with sodium carbonate. Name the gas evolved. How can it be tested ?
(c) State the principle on which the cleansing action of soap is based.

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જવાબ : (a) Carboxylic acids (organic acids) are less ionised in solution as compared to mineral acids (HCl, HNO3, H2SO4 etc.) Due to this reason, these are weaker acids than the mineral acids.
(b) Take a small volume of ethanoic acid in a tube. Add a few drops of sodium carbonate (Na2CO3) solution prepared in water to the tube. A colourless gas with brisk effervescence will evolve. When the gas is passed through lime water, it will become milky.

Previous Year Question Papers for CBSE Class 10 Science Chapter 4 Carbon and Its Compounds 28
(c) The cleansing action of soap is based on its tendency to act as a bridge between water and oil drops containing dirt particles. As a result, oil and water get mixed. They form a stable emulsion also called micelle. This helps in removing oil drops containing dirt particles from clothes. The clothes become clean.


(a) What are homologous series of compounds ? List any two characteristics of homologous series.
(b) What would be observed by adding a 5% solution of alkaline potassium permanganate drop by drop to warm ethanol taken in a test tube ? (c) Write the name of the compound formed during the chemical reaction. How would you distinguish experimentally between an alcohol and a carboxylic acid on the basis of a chemical property.

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જવાબ : (a) Homologous series represent different families of organic compounds into which these are divided. Two characteristics of homologous series are listed.

  1. All the members in a particular homologous series of family have the same characteristic functional group. For example, in organic acids, the functional group is carboxyl group (—COOH).
  2. Any two consecutive members in a particular family have the same common difference of CH2 in their molecular formulae. For example, the first three members of the family of alkanes are : CH4 (methane), C2H6 (ethane) and propane (C3H8).
(b) On adding a 5% solution of alkaline potassium permanganate to ethanol, it will be oxidised to ethanoic acid.
The pink colour of the solution will get discharged upon warming.
Previous Year Question Papers for CBSE Class 10 Science Chapter 4 Carbon and Its Compounds 26
(c) A carboxylic acid gives a brisk effervescence when an aqueous solution of sodium hydrogen carbonate (NaHCO3) is added to it. This is due to the evolution of CO2 gas. However, alcohol will not give any reaction.
Previous Year Question Papers for CBSE Class 10 Science Chapter 4 Carbon and Its Compounds 27


Explain the mechanism of the cleaning action of soaps.

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જવાબ : We all know that soap is used to remove dirt and and grime from substances. Generally dirt and grime get stuck because they have an oily component, which is difficult to remove, by plain brushing or washing by water. A soap molecule has two parts, a head and a tail i.e. the long chain organic part and the functional group –COO Na+.
A soap molecule has a tadpole like structure shown below.
The organic part is water insoluble but is soluble in organic solvents or in oil or grease. The ionic part is soluble in water, as water is a polar solvent. When soap is added to water in which dirty clothes are soaked, the two parts of the soap molecule dissolve in two different mediums. The organic tail dissolves in the dirt, grime or grease and the ionic head dissolves in water. When the clothes are rinsed or agitated, the dirt gets pulled out of the clothes, by the soap molecule. In this way soap does its cleaning work on dirty and grimy clothes or hands.

NCERT Solutions for Class 10 Science Chapter 4 Carbon and its Compounds Q22
The soap molecules actually form a closed structure because of mutual repulsion of the positively charged heads. This structure is called a micelle. The micelle pulls out the dirt and grime more efficiently.


Give a test that can be used to differentiate chemically between butter and cooking oil.

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જવાબ : Bromine water test can be used to differentiate chemically between butter and cooking oil. Add bromine water to a little of cooking oil and butter taken in separate test tubes. a. Decolourising of bromine water by cooking oil (unsaturated compound)
b. Butter (saturated compound) does not decolourise bromine water


Which among the following will undergo additional reactions?

C2H5, C3H8, C3H6, C2H2 and CH4

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જવાબ : Alkenes and alkynes (unsaturated hydrocarbons) undergo addition reactions. From the above hydrocarbons C2H2 is an alkyne, whereas C3H6 is an alkene. So, C3H6 and C2H2 will undergo addition reactions.


Define the formation of scum when hard water is treated with soap.

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જવાબ : The precipitate form of scum is formed when soap is used for washing clothes. With hard water, a large amount of soap is wasted in reacting with the calcium and magnesium ions of hard water to form an insoluble precipitate. The precipitate form formed by the action of hard water on soap, sticks to the clothes being washed and interferes with the cleaning ability of the additional soap. This makes the cleaning of clothes difficult.


Why does micelle formation happen when soap is added to water? Will a micelle be formed in other solvents such as ethanol also?

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જવાબ : Micelle formation takes place when soap is added to water. This is because when soap is added to water in which dirty clothes are soaked, the two parts of the soap molecule dissolves in two different mediums. The organic tail dissolves in the dirt, grime or grease and the ionic head dissolves in water. When the clothes are rinsed or agitated, the dirt gets pulled out of the clothes in the water by the soap molecule. In this way the soap does its cleaning work on dirty and grimy clothes or hands.
The soap molecules actually form a closed structure because of mutual repulsion of the positively charged heads. This structure is called a micelle.


How does the ethanol and Ethanoic acid be differentiated on the basis of their physical and chemical properties?
 

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જવાબ : (i) Ethanol has a pleasant smell whereas ethanoic acid has the smell of vinegar.
(ii) Ethanol has a burning taste whereas ethanoic acid has a sour taste.
(iii) Ethanol has no action on litmus paper whereas ethanoic acid turns blue litmus paper red.
(iv) Ethanol has no reaction with sodium hydrogencarbonate but Ethanoic acid gives brisk effervescence with sodium hydrogencarbonate.


What so you understand by homologous series? Explain with an example.

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જવાબ : Homologous series is a series of compounds with a similar general formula, possessing similar chemical properties due to the presence of the same functional group, and shows a gradation in physical properties as a result of increase in molecular size and mass. For example, methane has a lower boiling point than ethane since it has more intermolecular forces with neighbouring molecules. This is because of the increase in the number of atoms making up the molecule.


Explain with diagram the cleansing action of soaps.

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જવાબ : When a dirty cloth is put in water containing dissolved soap, then the hydrocarbon end of the soap molecules in micelle attach to the oil or grease particles present on the surface of dirty cloth. In this way the soap micelle entraps the oily or greasy particles by using its hydrocarbon ends. The ionic ends of the soap molecules in the micelles, however, remain attached to water. When the dirty cloth is agitated in soap solution, the oily and greasy particles present on its surface and entrapped by soap micelles get dispersed in water due to which the soap water becomes dirty but the cloth gets cleaned. The cloth is cleaned thoroughly by rinsing in clean water a number of times.
NCERT Solutions for Class 10 Science Chapter 4 Textbook Chapter End Questions Q15


Write down a test that can be used to differentiate chemically between butter and cooking oil.

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જવાબ : We know that Butter is a saturated carbon compound while cooking oil is an unsaturated carbon compound. An unsaturated compound decolourises bromine water, while a saturated compound cannot decolourise it. So we can distinguish chemically between a cooking oil and butter by the bromine water. Add bromine water to a little of cooking oil and butter taken in separate test-tubes.

  • Cooking oil decolourises bromine water showing that it is an unsaturated compound.
  • Butter does not decolourise bromine water showing that it is a saturated compound.


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a. . Organic compound formed by reaction of acid and alcohol
 

Graphite

b. Self linking ability of carbon
 

Ester

c. Substance which has cleansing action in hard water

Detergent

d. Allotrope of carbon used in lubrication

Catenation

 

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જવાબ :

a. Ester
b. Catenation
c. Detergent

a. First homologue of alkene series

Diamond

b. The organic compounds having the same molecular formula but different structures

Hydrocarbons

c. Allotrope of carbon used as glass cutter
 

Ethene

d. Compounds of carbon and hydrogen
 

Isomers

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જવાબ :

a. Ethene
b. Isomers
c. Diamond
d.  Hydrocarbons

જવાબ :

(a) – (iii)
(b) – (i)
(c) – (iv)
(d) – (ii)

જવાબ :

(a) – (ii)
(b) – (iii)
(c) – (iv)
(d) – (i)

જવાબ :

(a) – (iv)
(b) – (i)
(c) – (ii)
(d) – (iii)

જવાબ :

(a) – (iv)
(b) – (iii)
(c) – (ii)
(d) – (i)

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Carbon and Its Compounds

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