BITSAT2011ChemistryPractical ChemistryActual
H ₂ ~S gas when passed through a solution of cations containing HCl precipitates the cations of second group of qualitative analysis but not those belonging to the fourth group. It is because
Options
- Apresence of HC1 decreases the sulphide ion concentration.
- Bsolubility product of group II sulphides is more than that of group IV sulphides.
- Cpresence of HCl increases the sulphide ion concentration.
- Dsulphides of group IV cations are unstable in HC 1
Correct answer
A. presence of HC1 decreases the sulphide ion concentration.
Step-by-step solution
IV ^ th group needs higher S ²⁻ ion concentration. In presence of HCl , the dissociation of H ₂ ~S decreases hence produces less amount of sulphide ions due to common ion effect, thus HCl decreases the solubility of H ₂ ~S which is sufficient to precipitate II ^ nd group radicals.