CBSE Solutions for Class 10 Maths

Select CBSE Solutions for class 10 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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(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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Ethene

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

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Spurious liquor

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

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Dehydration

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

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Hydrogenation

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

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Pyrolysis

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

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Acetic acid

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

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Formalin

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

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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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Ammoniacal cuprous chloride

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

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Calcium carbide

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

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Alcohol

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

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Carboxylic acid

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

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Vinegar

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

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Molybdenum oxide

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

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Methane

What do you understand by oxidizing agents?

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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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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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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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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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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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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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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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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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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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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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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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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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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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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.

Explain the mechanism of the cleaning action of soaps.

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Answer :

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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Answer :

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. <font
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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Answer :

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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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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Answer :

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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Answer :

(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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Answer :

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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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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Answer :

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.

For the given reaction, match column I with column II and mark the correct option from the codes given below.
Fe2O3 + xCO → yFe + xCO2

Column I

Column II

(a) Oxidising agent

(p) 2

(b) Reducing agent

(q) 3

(c) x

(r) Fe2O3

(d) y

(s) CO

Column I

Column II

(a) Oxidising agent

(r) Fe2O3

(b) Reducing agent

(s) CO

(c) x

(q) 3

(d) y

(p) 2

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Column I

Column II

(a) Oxidising agent

(r) Fe2O3

(b) Reducing agent

(s) CO

(c) x

(q) 3

(d) y

(p) 2

Answer :

(a) → (q)
(b) → (r)
(c) → (p)
(d) → (s)

Symbols

Meaning

(a) →

(p) Aqueous

(b) (g)

(q) Yield or gives

(c) Δ

(r) Heat

(d) (aq)

(s) Liberation of gas

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Answer :

Symbols

Meaning

(a) →

(q) Yield or gives

(b) (g)

(s) Liberation of gas

(c) Δ

(r) Heat

(d) (aq)

(p) Aqueous

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Browse & Download CBSE Books For Class 10 - All Subjects

The CBSE Books for class 10 are designed as per the syllabus followed Gujarat Secondary and Higher Secondary Education Board provides key detailed, and a through solutions to all the questions relating to the GSEB textbooks.

The purpose is to provide help to the students with their homework, preparing for the examinations and personal learning. These books are very helpful for the preparation of examination.

For more details about the GSEB books for Class 10, you can access the PDF which is as in the above given links for the same.

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