CBSE Class 10 Science Acids Bases and Salts Assignment Set C

Question : Which of the following is a double salt ? 
(A) Blue Vitriol
(B) Glauber’s salt
(C) Potash Alum
(D) Potassium Ferrocyanide
Answer : C

Question : The reagent obtained by dissolving Copper sulphate in aqueous solution of Citric acid and Sodium carbonate is...................
(A) Bayer’s reagent
(B) Tollen’s reagent
(C) Fehling reagent
(D) Benedict reagent
Answer : D

Question : When Sodium carbonate (Na₂CO₃) reacts with Silica (SiO₂) gives.................
(A) Soda Glass
(B) Water glass
(C) Crook’s glass
(D) Pyrex glass
Answer : B

Question : In order to decrease the role of setting of Cement, which compound is mixed in it ?
(A) Ca(OH)₂ (Slaked lime)
(B) CaCO₃ (Calcium Carbonate)
(C) CaSO₄.2H₂O (Gypsum)
(D) Al₂O₃ (Alumina)
Answer : C

Question : Which one of the following is not base ? 
(A) B(OH)₃
(B) KOH
(C) Ca(OH)₂
(D) NH₄OH
Answer : A

Question : The nature of solution when sodium carbonate is dissolved in water will be
(A) acidic
(B) basic
(C) neutral
(D) amphoteric
Answer : B

Question : pH of a solution is zero. The nature of this solution is 
(A) acidic
(B) basic
(C) neutral
(D) amphoteric
Answer : A

Question : The difference in number of crystalline water molecules in a molecule of gypsum and a molecule of plaster of Paris is 
(A) 5/2
(B) 2
(C) 1/2
(D) 3/2
Answer : D

Question : Match the following : 
(a) formic acid            (i) dehydrating agent
(b) Nitric acid             (ii) organic acid
(c) Electrolyte            (iii) Mineral acid
(d) Conc. H₂SO₄        (iv) Nacl
(A) (a) (ii), (b) (iii), (c) (iv), (d) (i)
(B) (a) (i), (b)(ii), (c) (iii), (d) (iv)
(C) (a) (iii), (b)(i), (c) (iv), (d) (ii)
(D) (a) (iv), (b)(iii), (c) (i), (d) (ii)
Answer : A

Question : A milkman added a small pinch of baking soda of fresh milk which has pH close to 6. As a result, pH of the medium
(A) became close to 2
(B) became close to 4
(C) did not undergo any changes
(D) became close to 8
Answer : D

Question : Which of the following salts does not contain any water of crystallisation ?
(A) blue vitriol
(B) washing soda
(C) baking Soda
(D) gypsum
Answer : C

Question : The substance which is chemically resistant and can hold aqua regia
(A) Ceramics
(B) Glass
(C) Fibre
(D) Thermosetting plastic
Answer : B

Question : Skin becomes yellow in conc. HNO₃ as 
(A) HNO₃ acts as an oxidizing agent
(B) HNO₂ acts as a dehydrating agent
(C) Nitro-cellulose is formed
(D) The proteins are converted into xantho proteins
Answer : A

Question : Match the items of column I with the items of column II 
Column – I (Polymers)       Column – II
a. aq. NaCl solution           i. Acidic
b. aq. Na2CO3 solution     ii. Basic
c. aq. NH₄Cl solution        iii. Neutral
d. aq. CaO solution           iv. Amphoteric
(A) c-i, d-iii, b-ii, a-i
(B) d-i, b-iv, a-iii c-iv
(C) a-iii, b-ii, c-i, d-iii
(D) b-ii, a-iii, d-ii, c-i
Answer : D

Question : The pH of pure water at 25°C is 7. If water is heated to boil, then 
(A) pH will decrease and water will become acidic
(B) pH will increase and water will become basic
(C) pH will decrease but water will remain natural
(D) pH will remain 7
Answer : C

Question : Which of the following is pH of basic solution ?
(A) 7
(B) 4.2
(C) 6.9
(D) 10.2
Answer : B

Question : Which reagent is able to dissolve gold and platinum ? 
(A) Nitric acid
(B) Aqua-regia
(C) Hydrochloric acid
(D) Sulphuric acid.
Answer : B

Question : The conjugate base of H₂PO₄^– is : 
(A) PO₄^3–
(B) P₂O₅
(C) H₃PO₄
(D) HPO₄^2–
Answer : D

Question : What is the conjugate base of OH^– ? 
(A) O₂
(B) H₂O
(C) O^–
(D) O^2–
Answer : D

Question : Hydrogen ion concentration in mol/L in a solution of pH = 5.4 will be :
(A) 3.98 × 10⁸
(B) 3.88 × 10⁶
(C) 3.68 × 10^–6
(D) 3.98 × 10^–6
Answer : D

Question :Three reactions involving H₂PO₄^– are given below :
(i) H₃PO₄ + H₂O → H₃O⁺ + H₂PO₄^–
(ii) H₂PO₄^– + H₂O →  HPO₄^2– + H₃O⁺
(iii) H₂PO₄^– + OH– →  H₃PO₄+ O^2–
In which of the above, does H₂PO₄^– act as an acid ?
(A) (ii) only
(B) (i) and (ii)
(C) (iii) only
(D) (i) only
Answer : A

Question : How many litres of water must be added to 1 litre an aqueous solution of HCl with a pH of 1 to create an aqueous solution with pH of 2 ? 
(A) 0.1 L
(B) 0.9 L
(C) 2.0 L
(D) 9.0 L
Answer : D

Question : The substance not likely to contain CaCO₃ is : 
(A) calcined gypsum
(B) sea shells
(C) dolomite
(D) a marble statue
Answer : A

Question : Tooth pastes are generally 
a. natural
b. acidic
c. basic
d. neutral
Answer : C
Explanation: Toothpastes are generally basic because their function is to react with the excess acid in our mouth and thus prevent tooth decay. 

Question : In the following schematic diagram for the preparation of hydrogen gas as shown in the figure, what would happen if the following changes are made?

i. In place of zinc granules, same amount of zinc dust in taken in the test tube.

ii. Instead of dilute sulphuric acid, dilute hydrochloric acid is taken.

iii. In place of zinc, copper turnings are taken.

iv. Sodium hydroxide is taken in place of dilute sulphuric acid and the test tube is heated. 

Answer : i. Since the zinc dust has a larger surface area than zinc granules. If the same amount of zinc dust is taken in the test tube then the reaction will be comparatively faster and hydrogen gas will evolve with greater speed.

ii. With dilute hydrochloric acid, almost the same amount of gas is evolved.

iii. With copper turnings, hydrogen gas will not evolve because copper is less reactive and it will not displace hydrogen from the acid. Hence, no reaction will take place.

iv. Zinc also reacts with NaOH. So, if sodium hydroxide is taken, then hydrogen gas will be evolved.

 

1- MARKS QUESTIONS

Question : Curd is not kept in copper and brass vessels. Why? 

Question : Pick up acids, bases and salts from the list given below.

HCl, NaCl, KOH, Ca(OH)₂, H₂CO₃, H₃PO₄, NH₄OH, CuSO₄, Na₂CO₃

Question : P & Q are aqueous solutions of sodium chloride and sodium hydroxide respectively. Which of these will turn blue litmus red and which red litmus blue?

Question : Two solutions A and B have pH 5 and 9 respectively. Which solution has higher hydrogen ion concentration and Why?

Question : A farmer is advised to sprinkle quick lime in his crop field. What would be the problem with the pH of the soil?

Question : How does the flow of acid rain water into a river makes the survival of aquatic life difficult.

2 MARKS QUESTIONS

Question : Tooth enamel is one of the hardest substance in our body.How does it undergo damage due to eating chocolates and sweets?How do toothpastes prevent this damage? 

Question : Write two properties each of acids and bases.