Assertion (A): `Sb^(3+)` is not precipitated as sulphide when `H_(2)S (g)` is passed in alkaline solution.
Reason (R) : `[S^(2-)]` ion in basic medium is inadequate for precipitation.

Options

A. If both (A) and (R) are correc, and (R) is the correct explanation of (A).
B. If both (A) and (R) are correct but (R) is not the correct explanation of (A).
C. If (A) is correct, but (R) is incorrect.
D. If (A) is incorrect, but (R) is correct.

Answer

C

Explanation

`(A)` is correct but `(R)` is false.
Correct `(R) : Sb^(3+)` is precipitated in group `II B` by `H_(2)S` in acidic medium `(dil HCI)`. In acidic medium `[S^(2-)]` decreases so that the radicals of group `IV` are not precipitated. Since the `k_(sp)` of the sulphides of `II` group is less than the `K_(sp)` of the sulphides of `IV` group.