Question

Calcium acetate on heating gives the compound with formula:
(A) ${\text{C}}{{\text{H}}_{\text{3}}}{\text{COC}}{{\text{H}}_{\text{3}}}$
(B) ${\text{C}}{{\text{H}}_{\text{3}}}{\text{COOH}}$
(C) ${\text{C}}{{\text{H}}_{\text{3}}}{\text{OH}}$
(D) ${\text{C}}{{\text{H}}_{\text{3}}}{\text{COOC}}{{\text{H}}_{\text{3}}}$

Answer 1

To answer this question, you must recall the decomposition reaction of calcium acetate. Calcium acetate is an ionic compound made up of a calcium ion and two acetate ions. On heating, the compound undergoes decomposition diving two different compounds, one organic and one inorganic salt.

Complete step by step solution
Calcium acetate is the calcium salt of ethanoic acid or acetic acid and it has the chemical formula ${\left( {{\text{C}}{{\text{H}}_{\text{3}}}{\text{COO}}} \right)_{\text{2}}}{\text{Ca}}$ . Systematically the salt would be named as calcium ethanoate but is generally known as calcium acetate. It may also be referred to as the acetate of lime. It commonly exists as a monohydrate salt, i.e. with one molecule of water off crystallization present with each molecule of the salt. As a result, the anhydrous form of the salt is highly hygroscopic.
The salt is prepared by adding hydrated lime or calcium carbonate in vinegar. The reaction of the formation can be given as:
${\text{CaC}}{{\text{O}}_{\text{3}}} + {\text{2C}}{{\text{H}}_{\text{3}}}{\text{COOH}}{\left( {{\text{C}}{{\text{H}}_{\text{3}}}{\text{COO}}} \right)_{\text{2}}}{\text{Ca}} \to {\left( {{\text{C}}{{\text{H}}_{\text{3}}}{\text{COO}}} \right)_{\text{2}}}{\text{Ca}} + {{\text{H}}_{\text{2}}}{\text{O}} + {\text{C}}{{\text{O}}_{\text{2}}}$
When heated, the calcium salts of carboxylic acids, i.e. calcium carboxylates undergo decomposition to form aldehydes or ketones depending upon the carboxylate group present. When calcium acetate is heated, we get calcium carbonate and acetone as the products. The reaction can be written as:
${\left( {{\text{C}}{{\text{H}}_{\text{3}}}{\text{COO}}} \right)_{\text{2}}}{\text{Ca}}\xrightarrow[{}]{\Delta }{\text{C}}{{\text{H}}_{\text{3}}}{\text{COC}}{{\text{H}}_{\text{3}}} + {\text{CaC}}{{\text{O}}_{\text{3}}}$
This decomposition reaction requires slow heating and there is no rearrangement possible in the formation of acetone. Also calcium acetate is a cheap salt, so this reaction was initially used as a method of production of acetone before the discovery of the cumene process.
The correct option is A.

Note
Calcium acetate salt is used commonly for controlling the level of phosphorus in the blood of the people suffering from kidney diseases who are on dialysis.