The hydroxide insoluble in NH4OH + NH4Cl is

Question

The hydroxide insoluble in NH4OH + NH4Cl is (A)  Al(OH)3  (B)  Ca(OH)3  (C)  Zn(OH)2  (D)  Mg(OH)2

Tardigrade Admin · Accepted Answer

In qualitative analysis of basic radicals (cations only the hydroxides of IIIrd group radicals are insoluble in excess of

N H_{4} O H

solution)
When aluminum salt reacts with

N H_{4} O H

, then a white ppt of

A l (O H)_{3}

is obtained which is insoluble in excess of

N H_{4} O H

solution

A lC l_{3} + 3 N H_{4} O H \to 3 N H_{4} Cl + white ppt A l (O H)_{3}

The hydroxide of iron, chromium and aluminium are insoluble in excess of

N H_{4} O H

solution

Q. The hydroxide insoluble in $N H_{4} O H + N H_{4} Cl$ is