Answer:
Option A
Explanation:
S2−+CuCl2→CuS↓ (black ppt.)
SO2−4+CuCl2→Soluble, thus
(a) CuCl2 selectively precipitates S2−
(b) S2−(soluble)+BaCl2→BaS↓
SO2−4(whiteppt.)+BaCl2→BaSO4↓
(b) precipitates SO2−4 and not S2−
(c) S2−(black.ppt)+Pb2+→PbS↓
SO2−4(white.ppt)+Pb2+→PbSO4↓
S2− and SO2−4, both are precipitated.
(d) S2−+Na2[Fe(CN)]5NO→Na4[Fe(CN)]5NOS]
Sodium nitroprusside (purple colour)
But no colour with SO2−4