Single Correct MCQs: Analytical Chemistry | Question Bank for JEE Main & Advanced (350+ Tests) PDF Download

Q.1. The product of reaction of an aq. solution of Bi³⁺ salt with sodium thiosulphate gives
(a) Bi₂S₃
(b) Na₃[Bi(S₂O₃)₃]
(c) Na[Bi(S₂O₃)₂]
(d) [Bi₂(S₂O₃)₂]Cl₂

Correct Answer is option (a)
3Na₂S₂O₃ + BiCl₃ = Na₃[Bi(S₂O₃)₃] + 3NaCl
Bi2(S₂O₃)₃ + 3H₂O = Bi₂S₃ + 3H₂SO₄

Q.2. Borax bead test is not given by
(a) an aluminium salt
(b) a cobalt salt
(c) a copper salt
(d) a nickel salt

Correct Answer is option (a)
As only coloured salts gives coloured bead hence B, C D can not be right answers.

Q.3. The ion that cannot be precipitated by both HCl and H₂S is
(a) Pb²⁺
(b) Cu⁺
(c) Ag⁺
(d) Sn²⁺

Correct Answer is option (b)

Cu⁺disproportionates in the aqueous solution to a very large extent.

Thus, the concentration of Cu⁺ ion is very small and hence it cannot be precipitated.

Q.4. Aqueous solution of a salt (Y) is alkaline to litmus. On strong heating, it swells-up to give a glassy material. When conc. H₂SO₄ is added to a hot concentrated solution of (Y), white crystals of a weak acid separates out. Hence, the compound (Y) is
(a) Na₂SO₄.10H₂O
(b) Ca₂B₆O₁₁.10H₂O
(c) Na₂B₆O₁₁
(d) Na₂B₄O₇.10H₂O

Correct Answer is option (d)
(Y) is borax Na₂B₄O₇.10H₂O

Na₂B₄O₇ + H₂SO₄ + 5H₂O  → Na₂SO₄ + 4H₃BO₃

Q.5. A colourless salt (X) is soluble in water and also in alcohols and amines. On strong heating, (X) gives a brown gas (Y) and a grey residue. (X) dissolves in ammonia to give a solution (Z) which gives silver mirror with aldehydes. A solution of (X) is easily reduced by iron (II) sulphate. A solution of (X) also gives a brick red precipitate with potassium dichromate solution. Hence, choose the correct alternative.

(a) A
(b) B
(c) C
(d) d

Correct Answer is option (d)

Hence, D.

Q.6. Which of the following is prepared by heating its hydrated salt?
(a) Anhyd. AlCl₃
(b) Anhyd.SnCl₂
(c) Anhyd. SnCl₄
(d) None of the above

Correct Answer is option (d)
All these hydrated salts on heating gets hydrolysed and hence anhydrous salt cannot be prepared by simply heating the hydrated salts.

Q.7. H₂SO₄ is added while preparing a standard solution of Mohr’ salt to prevent
(a) hydration
(b) reduction
(c) hydrolysis
(d) complex formation

Correct Answer is option (c)
FeSO₄ + 2H₂O → Fe(OH)₂ + H₂SO₄ Addition of H₂SO₄ to this solution reverses the hydrolysis of FeSO₄.

Q.8. Tests on an aqueous solution of sodium salt having an anion X^n– gives the following results.

Which of the following could be X^n–?
(a) I–
(b)
(c) S^2–
(d)

Correct Answer is option (c)

Q.9. When KNO₂ is added to Co⁺⁺ salt in acetic acid medium, yellow ppt is formed. It is due to
(a) K₄ [CO(NO₂)₆]
(b) K₃ [CO(NO₂)₆]
(c) KCO[CO(NO₂)₆]
(d) None

Correct Answer is option (b)
Na₂CrO₄ + H₂SO₄  → Na₂Cr₂O₇

Q.10. Which of the following salt will not produce black ppt. on passing H₂S through their aqueous salt solutions in desired medium?
(a) CuSO₄
(b) PbCl₂
(c) CdSO₄
(d) NiCl₂

Correct Answer is option (b)
Since, CdS is a yellow solid.