Question

Can ${P_4}{O_{10}}$ change malonic acid to $C{O_2}$?
A.True
B.False

Answer 1

Hint: The chemical formula for malonic acid is $C{H_2}{(COOH)_2}$. ${P_4}{O_{10}}$ is known as phosphorus pentoxide. When malonic acid reacts with phosphorus pentoxide then tricarbon dioxide is generated along with pyrophosphoric acid.

Complete step by step answer:
Phosphoric acid: Its chemical formula is ${H_3}P{O_4}$. It is also known as orthophosphoric acid.
Pyrophosphoric acid: Its chemical formula is ${H_4}{P_2}{O_7}$. It is formed when two molecules of phosphoric react and one water molecule is removed from it.
Malonic acid: Its chemical formula is $C{H_2}{(COOH)_2}$.
Phosphorus pentoxide: Its empirical formula is ${P_2}{O_5}$and molecular formula is ${P_4}{O_{10}}$. It is formed when phosphorus is heated in sufficient amounts of oxygen. If phosphorus reacts in air containing insufficient amounts of oxygen then phosphorus in $(III)$ valency is produced.
There are two types of phosphorus: one is white and the second is red in colour. When red phosphorus is heated with hydrogen then phosphine$(P{H_3})$ is formed. White phosphorus catches fire by itself. They do not require any external heat to catch fire. Phosphorus catches fire by itself because phosphorus shows oxidation by air and heat is evolved in this process. So this process is exothermic in nature.
Now, coming to the question. In the question it is asked when malonic acid reacts with phosphorus pentoxide then what is the product. The reaction is as follows,
$2C{H_2}{(COOH)_2} + {P_4}{O_{10}} \to $$2{H_4}{P_2}{O_7} + 2{C_3}{O_2}$. By the reaction we can see that the product formed by the reaction of malonic acid and phosphorus pentoxide is pyrophosphoric acid and tricarbon dioxide and not carbon dioxide.
Hence the statement that malonic acid on reaction with phosphorus pentoxide from carbon dioxide is wrong.

Note:
Phosphorus can form different compounds on heating on the basis of concentration of oxygen gas present in the air. For example: if oxygen is in sufficient amounts then phosphorus pentoxide is formed and if oxygen is in insufficient amounts then phosphorus with valency three is formed which is ${P_4}{O_6}$ is formed.