NEET2005ChemistryIonic EquilibriumActual
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 HCl 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
- Dsulphide of group IV cations are unstable in HCl
Correct answer
A. presence of HCl decreases the sulphide ion concentration
Step-by-step solution
In qualitative analysis of cation of second group, H ₂ ~S gas is passed in presence of HCl , sulphide ions obtained is sufficient for the precipitation of second group cations in form of their sulphides due to lower value of their solubility product ( K _ sp ) . Hence, fourth group cations are not precipitated because they require for exceeding their ionic product to their solubility products and higher sulphide ions concentration due to their higher K _ sp which is not obtained here due to common ion effect. commo