Question

State the observation you make by adding ammonium hydroxide to the aqueous solution of aluminum chloride.

Answer 1

Double displacement reaction:

• Those reactions in which two compounds react by an exchange of ions to form two new compounds are called double displacement reactions.
• Example: ${\mathrm{Fe}}_2{\mathrm{O}}_3\left(\mathrm{s}\right)+6\mathrm{HCl}\left(\mathrm{aq}\right)\to 2\mathrm{Fe}{\mathrm{Cl}}_3\left(\mathrm{aq}\right)+3{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$

On adding Ammonium hydroxide to the aqueous solution of Aluminum chloride, the following observation is obtained :

• A white precipitate of Aluminum hydroxide$\left(\mathrm{Al}{\left(\mathrm{OH}\right)}_3\right)$ will be observed on adding Ammonium hydroxide $\left({\mathrm{NH}}_4\mathrm{OH}\right)$ to Aluminum chloride $\left({\mathrm{AlCl}}_3\right)$ under the double displacement reaction.

Reaction involved:

• ${\mathrm{AlCl}}_3\left(\mathrm{aq}\right)+3{\mathrm{NH}}_4\mathrm{OH}\left(\mathrm{aq}\right)\to \underset{(\mathrm{white}\mathrm{ppt})}{\mathrm{Al}{\left(\mathrm{OH}\right)}_3\left(\mathrm{s}\right)}+3{\mathrm{NH}}_4\mathrm{Cl}\left(\mathrm{aq}\right)$
• Hence, a white precipitate of Aluminum hydroxide will be observed.