Which of the following is a double salt ?

Options

A. Alum
B. Chrome alum
C. Microcosmic Salt
D. All of these

Answer

D

Explanation

All compounds that dissociate into two or more cations// anions completely on dissolving into water are known as double salts
General formula of alums
`A_(2)SO_(4)B_(2)(SO_(4))_(3)24H_(2)O` where A is monovalent redical while `B` is trivalent radicals
`{:(A_(2)SO_(4).B_(2)(SO_(4))_(3).24underset(darr)(H_(2)O),,,,),(2A1^(o+)+2B^(+3)+4SO_(4)^(2-)+24H_(2)O,,,,):}`
(b) Chrome alum implies `{:(K_(2)SO_(4).Cr_(2)(SO_(4))_(3).24underset(darr)(H_(2)O),,,,),(2K^(o+)+2Cr^(+3)+4SO_(4)^(2-)+24H_(2)O,,,,):}`
(c ) Microcosmic salt `{:(K_(2)SO_(4).Cr_(2)(SO_(4))_(3).24underset(darr)(H_(2)O),,,,),(2K^(o+)+2Cr^(+3)+4SO_(4)^(2-)+24H_(2)O,,,,):}` .