An aqueous solution of colourless metal sulphate M gives a white precipitate with `NH_4 OH`. This was soluble in excess of `NH_4 OH`. On passing `H_2 S` through this solution a white ppt. is formed. The metal M in the salt is

Options

A. Ca
B. Ba
C. Al
D. Zn

Explanation

`Zn^(+) +2NH_(4)OH to underset("White ppt")(Zn(OH)_(2))+2NH_(4)^(+)`
`Zn(OH)_(2)+2NH_(4)OH to underset("Soluble")((NH_(4))_(2)ZnO_(2))+2H_(2)O`
`(NH_(4))_(2)ZnO_(2)+H_(2)S to underset("White ppt.")(ZnS)+2NH_(4)OH`