p-Block Elements — JEE Advanced · 2020 · 27 Sep 2020 · Paper 2 Question with Solution

Choose the correct statement(s) among the following.

(A) $SnCl_{2} .2 H_{2} O$ is a reducing agent.✓ Correct
(B) $SnO_{2}$ reacts with KOH to form $K_{2} [Sn (OH)_{6}]$ .✓ Correct
(C)A solution of $PbCl_{2}$ in HCl contains $Pb^{2 +}$ and $Cl^{-}$ ions.
(D)The reaction of $Pb_{3} O_{4}$ with hot dilute nitric acid to give $PbO_{2}$ is a redox reaction.

Answer: (A), (B)

Solution

(A)

SnCl_{2} .2 H_{2} O

contains

Sn^{2 +}

, which can be oxidized to

Sn^{4 +}

. Hence it acts as a reducing agent. ✓

(B)

SnO_{2}

is amphoteric:

SnO_{2} + 2 KOH_{(aq.)} + 2 H_{2} O ⟶ K_{2} [Sn (OH)_{6}]

✓

(C)

PbCl_{2}

is sparingly soluble in water. In the presence of excess HCl, it can form

H_{2} [PbCl_{4}]

complex. The statement is ambiguous; the source solution suggests A, B or A, B, C could be correct, but the official answer is A, B. ✗

(D) The reaction:

Pb_{3} O_{4} + 4 HNO_{3} ⟶ PbO_{2} (↓) + 2 Pb (NO_{3})_{2} + 2 H_{2} O

Pb_{3} O_{4}

is a mixture (

2 PbO . PbO_{2}

). This is not a redox reaction — it's a disproportionation/separation. ✗

Correct: (A), (B)

JEE Advanced · 2020 · 27 Sep 2020 · Paper 2 · One or more correct options

JEE Advanced · 2020 · 27 Sep 2020 · Paper 2 · p-Block Elements

Solution

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