Question

Which gas is the acid anhydrides of carbonic acid?
(A) $S{O_2}$
(B) $C{O_2}$
(C) CO
(D) S

Answer 1

Hint: Carbonic acid is a chemical compound with the chemical formula ${H_2}C{O_3}$. Further, an acid anhydride is a compound that has two acyl groups bonded to the same oxygen atom. It is a non-metal oxide which reacts with water to form an acidic solution.

Complete step by step answer:
An acid anhydride is a compound that has two acyl groups (\[R - C = O\]) bonded to the same oxygen atom. Anhydrides are commonly when a carboxylic acid reacts with an acid chloride in the presence of a base.
Further, Carbonic acid is described as a respiratory acid because it is the only acid that is exhaled in the gaseous state by the human lungs. Moreover, it is a weak acid and forms carbonate and bicarbonate salts.
Carbonic acid is both weak and unstable and quickly dissociates into hydrogen ions (${H^ + })$and bicarbonate ions ($HC{O_3}^ - $).
Further, carbon dioxide is the acid anhydride of carbonic acid and when dissolved in water it participates in the following equilibrium:
$C{O_2} + {H_2}O\underset {} \leftrightarrows {H_2}C{O_3}$
However, only a small amount of carbon dioxide is converted into carbonic acid in the chemical equilibrium.

Hence, option B is correct.

Note: Carbonic acid is a very important compound with a wide range of applications. It helps in the transportation of carbon dioxide out of the body. It can be consumed orally in order to induce vomiting whenever required (such as in drug overdose cases). Moreover, it is widely used in the production of soft drinks, artificially carbonated sparkling wines and other bubbly beverages.