What do you observe when: ammonium hydroxide is added to iron (III) sulphate solution.

The given reactants are:

Ammonium hydroxide –${\mathrm{NH}}_4\mathrm{OH}$

Ferrous (III) sulfate – ${\mathrm{Fe}}_2{\left({\mathrm{SO}}_4\right)}_3$

When ammonium hydroxide is added to iron (III) sulfate solution, the chemical reaction takes place as-

 ${\mathrm{Fe}}_2{\left({\mathrm{SO}}_4\right)}_3+6{\mathrm{NH}}_4\mathrm{OH}\to \underset{ \mathrm{Ferric} \mathrm{hydroxide} }{2\mathrm{Fe}{\left(\mathrm{OH}\right)}_3}+3{\left({\mathrm{NH}}_4\right)}_2{\mathrm{SO}}_4$

Ferric hydroxide is obtained as a reddish-brown precipitate.

Hence, the correct option is D.