NON-MEATALS, D. Acid, Base and Salt

Total Questions: 56

11. Which acid is considered as a basic chemical in Industry? [43rd B.P.S.C. (Pre) 1999]

(a) H₂CO₃
(b) HNO₃
(c) H₂SO₄
(d) HCl

Correct Answer: (c) H₂SO₄

Solution:In the chemical industry, the sulphuric acid (H₂SO₄) is considered as a basic chemical or "king of chemicals" . Sulphuric acid is mainly used in petrochemical industries. It is used to refine metals, reduce corrosion of steel, refine oil and manufacture fertilizers. It is also used for cleaning purposes in the laboratory.

12. Which of the following is present in maximum amount in acid rain? [60th to 62nd B.P.S.C. (Pre) 2016]

(a) HCl
(b) HNO₃
(c) H₂SO₄
(d) H₂CO₃
(e) None of the above/More than one of the above

Correct Answer: (c) H₂SO₄

Solution:The sulphur dioxide and nitrous oxide emitted from atmospheric pollution, industrial effusions and other activities occurring in nature reach the atmosphere and react with oxygen and cloud water and fall on earth as sulphuric acid (H₂SO₄) and nitric acid (HNO₃) respectively. This is called Acid rain. The amount of sulphuric acid (H₂SO₄) in the acid rain is about 70-75% and it is the primary acid rain component.

13. The component(s) of acid rain is/are : [66th B.P.S.C. (Pre) (Re. Exam) 2020]

(a) HNO₃
(b) H₂SO₄
(c) CO₂
(d) Both (a) and (b)
(e) None of the above/More than one of the above

Correct Answer: (d) Both (a) and (b)

14. which acid is present in Acid Rain? [I.A.S. (Pre) 2001]

(a) Benzoic acid
(b) Acetic acid
(c) Nitric acid
(d) Oxalic acid
(e) None of the above

Correct Answer: (c) Nitric acid

Solution:

The sulphur dioxide and nitrous oxide emitted from atmospheric pollution, industrial effusions and other activities occurring in nature reach the atmosphere and react with oxygen and cloud water and fall on earth as sulphuric acid (H₂SO₄) and nitric acid (HNO₃) respectively. This is called Acid rain. The amount of sulphuric acid (H₂SO₄) in the acid rain is about 70-75% and it is the primary acid rain component.

15. An aqueous solution of copper sulphate is acidic in nature because the salt undergoes – [I.A.S. (Pre) 2001]

(a) dialysis
(b) electrolysis
(c) hydrolysis
(d) photolysis

Correct Answer: (c) hydrolysis

Solution:Copper sulphate reacts with water which produces strong acid H₂SO₄ and weak base Cu(OH)₂ as there is a process of hydrolysis. So it is acidic in nature.

CuSO₄ + 2H₂O → H₂SO₄ + Cu(OH)₂

16. Which is not a Lewis acid? [Jharkhand P.C.S. (Pre) 2013]

(a) AlCl₃
(b) BF₃
(c) NH₃
(d) FeCl₃

Correct Answer: (c) NH₃

Solution:The Lewis acids are lone pair acceptors. The Lewis bases are lone pair donors. Nitrogen in NH₃ has 5 electrons in which 3 of them are involved in bonding. That leaves one lone pair. This lone pair is available for bonding. Therefore, NH₃ is a Lewis base. AlCl₃, BF₃ and FeCl₃ are Lewis acids.

17. Assertion (A): To dilute sulphuric acid, acid is added to water and not water to acid. [I.A.S. (Pre) 1999]

Reason (R): Specific heat of water is very high.

(a) Both (A) and (R) are true, and (R) is the correct explanation of (A).
(b) Both (A) and (R) are true, but (R) is not a correct explanation of (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.

Correct Answer: (a) Both (A) and (R) are true, and (R) is the correct explanation of (A).

Solution:In order to dilute Sulphuric acid, acid is being added into water, which produces heat and energy. Water has a higher specific heat (heat capacity) than the acid, and so a vessel of cold water will absorb heat as acid is added. If water is added into acid then suddenly more heat would be generated and solution may boil very violently, splashing concentrated acid out of the vessel. So, acid is added to water to dilute sulphuric acid. Hence, both (A) and (R) are true and (R) is the correct explanation of (A).

18. Some metal oxides react with acid as well as base to produce salt and water. They are known as amphoteric oxides. The examples of amphoteric oxides are : [68th B.P.S.C. (Pre) 2022]

(a) CuO and ZnO
(b) Al₂O₃ and ZnO
(c) Al₂O₃ and CuO
(d) More than one of the above
(e) None of the above

Correct Answer: (b) Al₂O₃ and ZnO

Solution:

Amphoteric oxides have both acidic and basic properties. The oxides of aluminum (Al₂O₃) and zinc (ZnO) are good examples. Other common examples of amphoteric oxides include BeO, MnO₂, Cr₂O₃, SnO₂ and PbO. They react with acids and alkalis to form salts and water. The metals become cations in the former case and oxoanions in the latter. On the other hand, CuO is basic in nature, it is not amphoteric. Hence, option (b) is the correct answer.

19. Acids react with metal carbonates to liberate _______ gas. [68th B.P.S.C. (Pre) 2022]

(a) H₂
(b) CO₂
(c) CO
(d) More than one of the above
(e) None of the above

Correct Answer: (b) CO₂

Solution:Acids react with metal carbonates to liberate carbon dioxide (CO₂) gas. When an acid reacts with a metal carbonate, salt, water, and carbon dioxide are produced. Examples :
ZnCO₃ + 2HCl → ZnCl₂ + H₂O + CO₂↑
Na₂CO₃ + 2HCl → 2NaCl + H₂O + CO₂↑
FeCO₃ + H₂SO₄ → FeSO₄ + H₂O + CO₂↑

20. Limewater is turned milky by : [66th B.P.S.C. (Pre) 2010]

(a) CO
(b) CO₂
(c) O₂
(d) O₃
(e) None of the above/More than one of the above