Which of the following sulphides is soluble in water?

Options

A. `As_(2)S_(3)`
B. `Sb_(2)S_(3)`
C. `CuFeS_(2)`
D. `Al_(2)S_(3)`

Answer

4

Explanation

Only Group `1` and `2` metals and aluminimum from soluble sulphides. These readily hydrolyze in water, and as a result ,solution of sulphides are very basic:
`S^(2-)(aq.)+H_(2)O(l) hArr HS^(-) (aq.)+OH^(-)(aq.)`
These is enough hydrolysis of the hydrogen sulphide ,in turn , to give the solution a strong odour of hydrogen sulphide:
`HS^(-)(aq.)+H_(2)O(l) hArr H_(2)S(g)+OH^(-) (aq.)`
All other metal sulphides are very insoluble.