Question 12 Marks
State the observations you would make on adding ammonium hydroxide to aqueous solution of (i) Ferrous sulphate (ii) Aluminium chloride?
Answer
View full question & answer→i. When Ammonium Hydroxide is added to the Ferrous Sulphate solution then a dirty green ppt. of Ferrous Hydroxide is formed with Ammonium Sulphate by Double Displacement reaction.
$2 \mathrm{NH}_{4} \mathrm{OH}(\mathrm{aq})+\mathrm{FeSO}_{4}(\mathrm{aq}) \rightarrow \mathrm{Fe}(\mathrm{OH})_{2}(\mathrm{ppt})+\left(\mathrm{NH}_{4}\right)_{2} \mathrm{SO}_{4}(\mathrm{aq})$
ii. When Ammonium Hydroxide is added to Aluminium Cholride then a white ppt. of Aluminium Hydroxide is formed with Ammonium Choride by Double Displacement Reaction.
$3 \mathrm{NH}_{4} \mathrm{OH}(\mathrm{aq})+\mathrm{AlCl}_{3}(\mathrm{aq}) \rightarrow \mathrm{Al}(\mathrm{OH})_{3}(\mathrm{ppt})+3 \mathrm{NH}_{4} \mathrm{Cl}(\mathrm{aq})$
$2 \mathrm{NH}_{4} \mathrm{OH}(\mathrm{aq})+\mathrm{FeSO}_{4}(\mathrm{aq}) \rightarrow \mathrm{Fe}(\mathrm{OH})_{2}(\mathrm{ppt})+\left(\mathrm{NH}_{4}\right)_{2} \mathrm{SO}_{4}(\mathrm{aq})$
ii. When Ammonium Hydroxide is added to Aluminium Cholride then a white ppt. of Aluminium Hydroxide is formed with Ammonium Choride by Double Displacement Reaction.
$3 \mathrm{NH}_{4} \mathrm{OH}(\mathrm{aq})+\mathrm{AlCl}_{3}(\mathrm{aq}) \rightarrow \mathrm{Al}(\mathrm{OH})_{3}(\mathrm{ppt})+3 \mathrm{NH}_{4} \mathrm{Cl}(\mathrm{aq})$