Question

Anhydrous ${\text{AlC}}{{\text{l}}_3}$ is prepared by:
A. Reaction of ${\text{HCl}}$ and ${\text{Al}}$ metal.
B. Reaction of dry ${\text{HCl}}$ and heated ${\text{Al}}$ metal.
C. Passing ${\text{HCl}}$ gas over heated ${\text{Al}}$ metal
D. Reaction of ${\text{A}}{{\text{l}}_{\text{2}}}{{\text{O}}_{\text{3}}}$ with dil. ${\text{HCl}}$.

Answer 1

Hint: Aluminium chloride is produced by an exothermic reaction of aluminium and chlorine. The produced aluminium chloride is anhydrous in nature.

Complete step by step answer:
Anhydrous aluminium chloride is prepared by the reaction of dry hydrochloric acid and heated aluminium metal. The reaction is exothermic.
The reaction is,
${\text{6Al}} + {\text{6HCl}} \to {\text{2AlC}}{{\text{l}}_{\text{3}}} + {{\text{H}}_{\text{2}}}$
Thus, anhydrous ${\text{AlC}}{{\text{l}}_3}$ is prepared by reaction of dry ${\text{HCl}}$ and heated ${\text{Al}}$ metal.
Thus, the correct option is (B) reaction of dry ${\text{HCl}}$ and heated ${\text{Al}}$ metal.

Additional Information:
Properties of aluminium chloride are:
1. Aluminium chloride has low melting point and low boiling point.
2. Aluminium chloride is a poor conductor of electricity in its molten state.
3. The sublimation temperature of aluminium chloride is ${180^ \circ }{\text{C}}$.
4. Aluminium chloride is a good Lewis acid.
5. Aluminium chloride is anhydrous in nature.
6. Aluminium chloride is non-explosive, non-flammable and corrosive.
7. On contact with water, aluminium chloride reacts violently.

Note:
The other ways in which aluminium chloride can be prepared are as follows:
Reaction of aluminium metal with chlorine gas. The reaction is,
${\text{2Al}} + {\text{3C}}{{\text{l}}_{\text{3}}} \to {\text{2AlC}}{{\text{l}}_{\text{3}}}$
Displacement reaction in which aluminium metal displaces copper in copper chloride.
${\text{2Al}} + {\text{3CuC}}{{\text{l}}_{\text{2}}} \to {\text{2AlC}}{{\text{l}}_{\text{3}}} + 3{\text{Cu}}$