Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R. Assertion A : \(\mathrm{H}_{2} \mathrm{Te}\) is more acidic than \(\mathrm{H}_{2} \mathrm{~S}\). Reason R: Bond dissociation enthalpy of \(\mathrm{H}_{2} \mathrm{Te}\) is lower than \(\mathrm{H}_{2} \mathrm{~S}\). In the light of the above statements. Choose the most appropriate from the options given below.

(B) Both A and R are true and R is the correct explanation of A .

(A) Both A and R are true but R is NOT the correct explanation of A .

JEE Main · 2024 · 30 Jan 2024 · Shift 2 · p-Block Elements

Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R.
Assertion A :

H_{2} Te

is more acidic than

H_{2} S

.
Reason R: Bond dissociation enthalpy of

H_{2} Te

is lower than

H_{2} S

.
In the light of the above statements. Choose the most appropriate from the options given below.

(A)Both A and R are true but R is NOT the correct explanation of A .
(B)Both A and R are true and R is the correct explanation of A .✓ Correct
(C)A is false but R is true.
(D)A is true but R is false.

Answer: (B)

Solution

Acid strength of the group 16 hydrides increases down the group:

H_{2} O < H_{2} S < H_{2} Se < H_{2} Te

. As atomic size grows down the group the H–X bond lengthens and orbital overlap weakens, so the bond dissociation enthalpy falls; a weaker H–X bond releases

H^{+}

more readily, which is exactly why acidity rises down the group. Since the bond dissociation enthalpy of

H_{2} Te

is lower than that of

H_{2} S

H_{2} Te

ionises more readily and is the stronger acid — Reason R correctly explains Assertion A.

JEE Main · 2024 · 30 Jan 2024 · Shift 2 · Single correct option

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JEE Main · 2024 · 30 Jan 2024 · Shift 2 · p-Block Elements

Solution

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