Question

Heating of sodium acetate with soda lime (mixture of NaOH + CaO) is called:
A. dehydration
B. decarboxylation
C. dehydrogenation
D. dehydrohalogenation

Answer 1

Hint: In this reaction, the two reactants are NaOH and CaO. This mixture is known as soda lime. We know that, with the addition of CaO, NaOH becomes less reactive. The further reaction of soda lime with carboxylic acids is known as Oakwood Reaction.

Complete step by step answer:
We have to remember that the NaOH is hygroscopic in nature and it forms a sodium hydroxide solution when it is exposed to air.
We have to remember that the decarboxylation is a chemical reaction that removes a carboxyl group and releases carbon dioxide ($C{O}_2).$ As we know that the decarboxylation refers to a reaction of carboxylic acids, removing a carbon atom from a carbon chain.
As we know that soda lime has a very less tendency to absorb water. The solid sodium salt of a carboxylic acid is mixed with solid soda lime, and the mixture is heated. The given reaction involves removal of carbon dioxide molecules. Therefore, the reaction occurring is a decarboxylation reaction. The first reaction occurring between an acid and the soda lime forms sodium benzoate, and then a decarboxylation occurs. We have to remember that the product formed in this reaction is methane.
We can write the decarboxylation reaction of sodium acetate as,
$C{H}_{3}COONa\stackrel{NaOH+CaO}{\to }C{H}_4+N{a}_{2}C{O}_3$

So, the correct answer is Option B.

Note: We have to remember that the Calcium oxide (CaO) used in the above reaction is a metal oxide. Like other metal oxides it is a basic oxide as it gets dissolved in water to form calcium hydroxide. It is also known as quicklime or burnt lime which is widely used as a chemical compound. It is a white, caustic, alkaline, crystalline solid present at room temperature.