Question

The dehydrating agent used in the conversion of acetic acid into acetic anhydride is:

• A. concentrated sulphuric acid
• B. anhydrous calcium oxide
• C. anhydrous aluminium chloride
• D. phosphorus pentoxide

Answer 1

Answer: (D)

The dehydrating agent used in the conversion of acetic acid into acetic anhydride is ${\text{P}}_{\text{2}}{\text{O}}_{\text{5}}\text{.}$ $2C{H}_{3}COOH+P_2{O}_5\to \underset{\begin{array}{c}\text{Acetic}\\ \text{anhydride}\end{array}}{{(C{H}_{3}CO)}_{2}O}$ $\underset{\begin{array}{c}\text{Meta}\\ \text{phosphoric}\text{acid}\end{array}}{+2HP{O}_3}$