GSEB Solutions for ધોરણ ૧૦ English

જવાબ : greater than 7

જવાબ : gypsum

જવાબ : colorless

જવાબ : Mohr’s salt

જવાબ : slaked lime with chlorine

જવાબ : washing soda

જવાબ : Caustic soda

જવાબ : yellow

જવાબ : monobasic acid

જવાબ : neutralization

જવાબ : blue, red

જવાબ : greater

જવાબ : CaSO₄, Cl₂, H₂O

જવાબ : 7

જવાબ : Water of crystallization

જવાબ : Sodium chloride

જવાબ : acidic, less

જવાબ : baking soda

જવાબ : acid (HCl)

જવાબ : H⁺

જવાબ : OH^– ions/H₃O⁺ ions, dilution

જવાબ : CH₃COOH

જવાબ : bleaching powder.

જવાબ : Calcium hydroxide.

જવાબ : Sodium carbonate is the compound which is used for softening hard water.

જવાબ : The chemical equation for the reaction of Plaster of Paris and water is CaSO₄.1/2H₂O + 3/2H₂O → CaSO₄.2H₂O

જવાબ : Curd and sour food substances contain acids; these acidic substances combine with metal. This reaction turns food to poison which damage people’s health.

જવાબ : When an acid reacts with any metal, salt and hydrogen gas are formed. Metal + Acid → Salt + Hydrogen gas

જવાબ : As metal compound released is Calcium Chloride the gas evolved here is CO₂. Hence metal X should be Calcium Carbonate. Hence the reaction between Calcium Carbonate and HCl is CaCO₃ (s) + 2HCl (Aq) → CaCl₂( Aq) + CO₂ (g) + H₂O (l)

જવાબ : Charged particles are responsible for the conductance of electricity in an acid. These charged particles called as ions are the reason behind conductance of electricity in acid.

જવાબ : HCL does not give out Hydrogen ions, therefore HCL does not show any acidic behavior and color of the litmus paper remain the same on reacting with HCl gas.

જવાબ : While diluting an acid, it is recommended that the acid should be added to water and not water to the acid because if water is added to concentrated acid, it release huge amount of heat which may result in explosion and can cause acid burns o face, clothes and body parts. Hence it is safe to add acid to water but not water to acid.

જવાબ : When acid is added to water there will be a fixed amount of hydronium present in the fixed volume of solution. If we dilute the solution hydronium ion per volume of solution decrease, this in-turn decreases Hydronium concentration in the solution.

જવાબ : When base is dissolved in sodium hydroxide solution its hydroxide ions increase but it will reach saturation at some point. After saturation point hydroxide ion concentration is not affected even after adding base further.

જવાબ : In order to find the hydrogen ion concentration, we can use the rule that states, “The pH of any solution is inversely proportional to the hydrogen ion concentration”. Therefore, it means that the solution that has a lower pH number will have a higher hydrogen ion concentration. Hence, solution X will have a higher hydrogen ion concentration. In addition, solution Y will be basic and X will be acidic.

જવાબ : Hydrogen ion concentration decides the nature of the solution. If Hydrogen ion concentration increase then solution turns acidic and similarly if Hydrogen ion concentration decreases then solution turn basic.

જવાબ : Yes, Basic solutions have H⁺ ions, but hydroxide ions present in basic solution are more in basic solution. Hence Hydroxide ions turn solution to basic.

જવાબ : If the soil is acidic in nature (PH below 7) then such field should be treated with quick lime (calcium oxide) or slaked lime (calcium hydroxide) or chalk (calcium carbonate).

જવાબ : Answer is 10 because litmus paper turns blue when reacts with basic solution (PH more than 7).

જવાબ : Answer is HCl. Egg shells contain calcium carbonate, which on reaction with HCl liberates CO₂ gas which turns lime water to milky. CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂

જવાબ : Since 10 ml of NaOH requires 8 mL of HCL, 20 ml of NaOH require 8 x 2 = 16mL of HCl Hence the answer id option d 16mL.

જવાબ : Indigestion is due to excess production of acid in the stomach. Medicines used to treat indigestion are called as Antacid.

જવાબ : HCl is a strong acid whereas acetic is a weaker acid. Fizzing occurs because of the production of the hydrogen gas obtained due to reaction of the acid on the magnesium ribbon. Since HCl is a very strong acid there is a lot of liberation of hydrogen gas from test tube A. therefore, more fizzing take place in test tube A.

જવાબ : Fresh milk is turned to curd due to production of lactic acid. Lactic acid reduces the pH of the milk.

જવાબ : (a) He shifted the pH of the fresh milk from 6 to slightly alkaline to prevent milk from getting sour due to production of lactic acid. (b) This milk takes long time to set into curd because the lactic acid produced here first neutralizes the pH then the pH is reduced to turn milk to curd.

જવાબ : Plaster of Paris should be stored in moisture-proof container because moisture can affect plaster of Paris by slowing down the setting of the plaster because of hydration. This will turn plaster useless.

જવાબ : The reaction of the acid + base gives a product of salt + water, which is considered as neutralization reaction. Examples: NaOH + HCl → NaCl + H₂O Mg(OH)₂ + H₂CO₃ → MgCO₃ + 2H₂O

જવાબ :

જવાબ :

• Distilled water does not contain any ionic compounds in it.
• Whereas rainwater has a lot, more compounds.
• Rainwater has dissolved acidic gas such as carbon dioxide from the air and that forms carbonic acid. This means that it has hydrogen ions and carbonate ions. Therefore, with the presence of acids, rainwater can conduct electricity.

જવાબ : The acidic behavior from acids is because of the presence of hydrogen ions. Hydrogen ions can only be produced in the presence of water and therefore water is definitely needed if acids are to show their acidic behavior.

જવાબ : (i) Put the red litmus paper in all the test tubes, turn by turn. The solution which turns red litmus to blue will be a basic solution. The blue litmus paper formed here can now be used to test the acidic solution.
(ii) Put the blue litmus paper obtained above in the remaining two test-tubes, turn-by-turn. The solution which turns the blue litmus paper to red will be the acidic solution.
(iii) The solution which has no effect on any litmus paper will be neutral and hence it will be distilled water.

જવાબ : An important alkali commonly needed for laboratory work is sodium hydroxide. It can be prepared from sodium chloride by the process of electrolysis. This is called chlor-alkali process.
Electrolysis of aqueous solution of sodium chloride: When electricity is passed through an aqueous solution of sodium chloride commonly called brine, it decomposes into chloride and sodium. Sodium is collected at the cathode where it reacts with water to form sodium hydroxide. Chlorine is formed at the anode and is collected as a gas.

જવાબ : Acids are those chemical which produce hydrogen ions in its aqueous solution for example: Citric acid, sulphuric acid, hydrochloric acid etc.
Properties of Acids are
(i) it is sour in taste.
(ii) It turns blue litmus into red.
(iii) It turns methyl orange color into red.
(iv) Acids are corrosive in nature.

જવાબ : Bases are those chemical which produce hydroxide ions (OH-) in its aqueous solution for example: Sodium hydroxide, Calcium hydroxide, Magnesium hydroxide etc.
Properties of Bases are
(i) Base have bitter taste.
(ii) Base convert red litmus into blue.
(iii) Base convert methyl orange color into yellow.
(iv) Base converts the color of Phenolphthalein into pink.
(v) Base does not react with metal.
(vi) Base does not react with metal carbonate and metal hydroxide carbonate due to its basic nature.
(vii) Only alkali bases are good conductor of electricity.

જવાબ : Litmus solution is a purple dye which is extracted from plant lichen. This dye is used an indicator to tests for acids and bases. When litmus solution is neither acidic nor basic, its color is purple. Acids change the color of blue litmus to red. Bases change the red color to blue.

જવાબ : When we dilute an acid with water then addition of acid in water is a correct way of dilution because when water is added into acid then exothermic reaction takes place and lots of heat comes out from the test tube. Due to which it can harm us while acid is added to water then endo thermic reaction take place due to assumption of heat in water.

જવાબ : pH scale is a scale for measuring hydrogen ions concentration. pH range between 0 to 14 thus, pH is a number which indicate the acidic or basic nature of a solution. The neutral value of pH is 7. A value less than 7 represent an acidic solution, while a value of more than 7 represent the basic nature of the solution.
Importance of pH in our daily life:
(i) pH of soil in the backyard: Every plant requires a specific pH for healthy growth. The optimum pH required for growth of a plant can be known by finding the pH of the place where such plant grow.

જવાબ : i) Chemical Name: Sodium: Bi carbonates
(ii) Chemical Formula: NaHCO3
(iii) Formation: NaCl + CO2 + H2O → NH4Cl + NaHCO3
(iv) Color and state: It is a white crystalline solid.
(v) Action of air: It is stable in air.
(vi)Solubility in water: It is soluble in water the solution will be alkali.
NOTE: We use baking soda in bakery or in kitchen because when we add baking soda in any substance it makes the food fluffy. Their carbon dioxide is responsible for the fluffiness of food like in cake. In bakery Baking powder is used instead of baking soda because baking powder contains mild acid like tartaric acid.
(vii) Uses of Baking soda: It is used in kitchen.
It is also used in medicine as antacid.
It is used in soda acid fire extinguisher.

જવાબ : All living things are very sensitive to acids and too much acid can kill cells or stop proper working of cells. Concentrated acid are very dangerous and should never be handled without protection.
The following projection must be observed while dealing with acids.
(i) Never try to touch or taste acid which are used in the laboratory.
(ii) Never add water into concentrated acid otherwise bottle will break. Always add conc. Acid to water very slowly with continuous cooling under running water.

જવાબ : The old person was suffering from acute acidity. Antacid tablet contains sodium hydrogen carbonate (NaHCO₃). It reacts with the acid (HCl) formed because of acidity and neutralizes its effect. That is how the old person got relief.

જવાબ : Surgical bandages are made from Plaster of Paris. When applied on the fractured bones after making them wet, it changes into hard mass called Gypsum.

The hard mass keeps the bones in proper position and the gap is slowly filled because of calcification that is taking place on the broken parts. This helps in uniting broken bones and they change to a single piece again.

જવાબ : a) The solution with pH 7 is neutral. Its pH can be increased by adding a small amount of base like sodium hydroxide. Basic solutions have pH more than 7. Similarly, pH can be decreased by adding small amount of acid like hydrochloric acid. Acidic solutions have pH less than 7.
(b) The change in color of litmus from red to blue indicates that the solution is of basic nature with pH more than 7.
(c) Carbon dioxide can be liberated by reacting sodium carbonate solution with acid like dilute hydrochloric acid. This shows that the solution is of acidic nature with pH less than 7.

જવાબ : (i) Common salt contains the impurity of magnesium chloride (MgCl₂) which is of deliquescent nature. When exposed to atmosphere, it becomes moist. Therefore, common salt becomes sticky during the rainy reason.
(ii) Blue vitriol (CUSO₄.5H₂O) upon heating changes to anhydrous copper sulphate (CUSO₄) which is white in color.
(iii) Concentrated sulphuric acid is highly hygroscopic. It absorbs moisture from air and gets diluted. Since the volume increases, the acid starts flowing out of the bottle.

જવાબ : (a) The raw materials used are: NaCl, lime stone or CaCO₃ and NH₃.
(b) Sodium hydrogen carbonate (NaHCO₃) is sparingly soluble or less soluble in water and gets separated as a preciptate while NH₄Cl remains in solution. The precipitate is removed by filtration.
(c) Sodium hydrogen carbonate is converted to sodium carbonate upon heating.

જવાબ : (a)

1. Red litmus has no action on dry ammonia gas because it does not release any hydroxyl ions (OH)^–
2. When passed through water, ammonia (NH₃) is converted to ammonium hydroxide (NH₄OH). It dissociates to give hydroxyl ions (OH) ^– and the solution is basic in nature. Red litmus acquires a blue color.

1. A green precipitate of ferrous hydroxide would be formed by double displacement reaction.
   
2. A white precipitate of aluminum hydroxide will be formed by double displacement reaction.
   

જવાબ : (a) An aqueous solution of an acid conducts electricity because in water, an acid (e.g. HCl) dissociates to give ions. Since the current is carried by the movement of ions, an aqueous solution of acid conducts electricity.
(b) Upon dilution, more of acid dissociates into ions. Therefore, concentration of [H₃O]⁺ ions increases upon dilution.
(c) Although more [H₃O]⁺ ions are formed upon dilution, but the number of ions per unit volume decrease. Therefore, pH will increase upon dilution.
(d)

1. Carbon dioxide gas would evolve accompanied by brisk effervescence.
   NaHCO₃ (s) + HCl (aq) ———–> NaCl(aq) + CO₂(g) + H₂O(aq)
2. Hydrogen gas would evolve accompanied by brisk effervescence.
   Zn(s) + 2HCl (aq) ———–> ZnCl₂(ag) + H₂(g)

જવાબ : (a) Upon heating sodium chloride with cone. H₂SO₄, hydrogen chloride gas evolves.
NaCl(s) + H₂SO₄(aq) ———> NaHSO₄ (aq) + HCl (g)
In the gaseous state, the acidic character is not shown because HCl does not release any H⁺ ions. In the presence of moisture (moist litmus paper), the gas changes to hydrochloric acid i.e., HCl(aq). The acid releases H⁺ ions and thus, shows acidic character. Therefore, moist blue litmus paper becomes red.
(b) When fresh milk changes to curd, the pH of the solution is likely to decrease. Actually, lactose present in milk gets converted to lactic acid when curd or yogurt is formed from milk. Therefore, the medium becomes more acidic and its pH decreases.
(c) The solution of sodium carbonate (Na₂CO₃) is of basic nature. Actually, the salt dissolves in water to produce NaOH (strong base) and H₂CO₃(weak acid). The blue litmus will not undergo any change in the basic medium. It will remain blue.

જવાબ : (i) The gas ‘X’ is H₂ and gas ‘Y’ is Cl₂
(ii) The chemical equation for the reaction is :

(iii) Cl₂ reacts with slaked lime to form bleaching powder.
Ca(OH)₂ + Cl₂ ———–> CaOCl₂ + H₂O.

જવાબ : (i) The strength of an acid is expressed in terms of its H⁺ ions releasing tendency in aqueous solution or in terms of its degree of dissociation
(α). Strong acids have large value of α (close to one) while weak acids have comparatively less value. For example, hydrochloric acid (HCl) is a strong acid while acetic acid (CH₃COOH) is a weak acid.
(ii) The available information suggests that the base ‘B’ present in the pellet is sodium hydroxide (NaOH). It is of deliquescent nature. It absorbs moisture from atmosphere and becomes sticky. The base reacts with dilute hydrochloric acid to form salt and water. This reaction is known as neutralization reaction.
NaOH (aq) + HCl(aq) ———–> NaCl (aq) + H₂O(l)

જવાબ : Sodium chloride (NaCl) also called common salt or table salt is the most essential part of our diet. Chemically it is formed by the reaction between solutions of sodium hydroxide and hydrochloric acid. Sea water is the major source of sodium chloride where it is present in the dissolved form along with other soluble salts such as chlorides and sulphates of calcium and magnesium. It is separated by some suitable method. Deposits of the salt are found in different parts of the world and are known as rock salt. The formation of rock salt is due to the slow evaporation of sea water which takes ages. When pure, it is a white crystalline solid. However, it is often brown due to the presence of impurities.
• Sodium Chloride — Essential for Life
Sodium chloride is quite essential for life. Biologically, it has a number of functions to perform such as in muscle contraction, in conduction of nerve impulses in the nervous system and is also converted into hydrochloric acid in the stomach which helps in the digestion of food. When we sweat, there is loss of sodium chloride and some. Other salts along with water. This leads to muscle cramps. The loss has to be compensated suitably by giving certain salt preparations to the patients. These are called electrolytes. Electoral powder is a very popular electrolyte.
• Chemicals from Common Salt
Sodium chloride is also a very useful raw material for different chemicals. A few out of these are : hydrochloric acid (HCl), washing soda (Na₂CO₃-10H₂O), baking soda (NaHCO₃) etc. Upon electrolysis, a strong solution of the salt (brine), sodium hydroxide, chlorine and hydrogen are obtained.
Apart from these, it is used in leather industry for the leather tanning. In severe cold, rock salt is spread on icy roads to melt ice. It is also, a fertilizer for sugar beet.

જવાબ : Sodium chloride (NaCl) also called common salt or table salt is the most essential part of our diet. Chemically it is formed by the reaction between solutions of sodium hydroxide and hydrochloric acid. Sea water is the major source of sodium chloride where it is present in the dissolved form along with other soluble salts such as chlorides and sulphates of calcium and magnesium. It is separated by some suitable method. Deposits of the salt are found in different parts of the world and are known as rock salt. The formation of rock salt is due to the slow evaporation of sea water which takes ages. When pure, it is a white crystalline solid. However, it is often brown due to the presence of impurities.
• Sodium Chloride — Essential for Life
Sodium chloride is quite essential for life. Biologically, it has a number of functions to perform such as in muscle contraction, in conduction of nerve impulses in the nervous system and is also converted into hydrochloric acid in the stomach which helps in the digestion of food. When we sweat, there is loss of sodium chloride and some. Other salts along with water. This leads to muscle cramps. The loss has to be compensated suitably by giving certain salt preparations to the patients. These are called electrolytes Electoral powder is a very popular electrolyte.
• Chemicals from Common Salt
Sodium chloride is also a very useful raw material for different chemicals. A few out of these are : hydrochloric acid (HCl), washing soda (Na₂CO₃-10H₂O), baking soda (NaHCO₃) etc. Upon electrolysis, a strong solution of the salt (brine), sodium hydroxide, chlorine and hydrogen are obtained.
Apart from these, it is used in leather industry for the leather tanning. In severe cold, rock salt is spread on icy roads to melt ice. It is also, a fertilizer for sugar beet.

જવાબ : (a)CuSO₄.5H₂O is hydrated copper sulphate. CuSO₄ is anhydrous copper sulphate.
Aim: To show crystalline salts contain water of crystallization.
Material Required: CuSO₄.5H₂O (Blue vitriol), boiling tube, burner, cork,
delivery tube, test tube, clamp stand.
Procedure: 1.Take 2g of CuSO₄.5H₂O in a boiling tube fitted in a clamp stand.
2. Observe its color. Fit it with cork and delivery tube bent at two right angles which dips into a test tube.
3. Heat crystals in boiling tube.
4. Observe vapors being condensed in test tube.
5. Cool the crystals and add few drops of water into it.
Observation: Water vapors get condensed in a test tube and color
of blue crystals changes into white. On adding water to anhydrous copper sulphate it changes into blue again.
Chemical Reaction:

Conclusion : Crystalline substances have water of crystallization which is lost on heating. When we add water inCuSO₄till a saturated solution is formed. On cooling, it gets converted into CuSO₄.5H₂Ocrystals and it shows that both are inter convertible.

જવાબ : (a) Our stomach has pH equal to 2. Antacids neutralize excess of acid in our body and gives relief from hyperacidity. Sodium hyrogencarbonate is one of such antacid.
(b) pH will decrease as it turns to curd because curd is acidic due to the presence of lactic acid.
(c) It takes longer time to set as curd as bacteria do not work well in presence of sodium hyrogencarbonate, i.e. fermentation will take place slowly.
(d) Toothpastes are basic in nature. They neutralize the acid formed in mouth which causes tooth decay.

જવાબ : Strong acids are those acids which are completely ionized in aqueous solution. Weak acids are those which do not ionize completely in aqueous solution. Strong acid: HCl,  HNO₃,H₂SO₄ Weak acid: Citric acid, acetic acid, formic acid.

જવાબ :

(c) A-(iii), B-(iv), C-(i), D-(ii)

જવાબ :

જવાબ :

જવાબ :

જવાબ :

જવાબ :

1. Phenolphthalein
2. Gypsum
3. Nettle
4. Acid

જવાબ :

a. Hydrogen

b. Neutralisation

c. Base

d. Antacid

જવાબ :

Column (A) Column (B)

(a) Lactic acid (iv) Curd

(b) Acetic acid (iii) Vinegar

(c) Citric acid (ii) Lemon