Question

Which of the following is not soluble in water?
(A) ${{H}_{2}}$
(B) ${{O}_{2}}$
(C) $S{{O}_{2}}$
(D) $C{{O}_{2}}$

Answer 1

Water is a polar solvent. Polar solvent means it will dissociate into ions (Cation and Anion). ‘Like dissolves in like’ means polar compounds are soluble in polar solvents only. Nonpolar compounds are soluble in nonpolar solvents only.

Complete step by step solution:
-We know that water is a polar solvent.
-Now we have to check which compounds are going to dissolve in the water and which compounds are not going to soluble in the water among the given options.
-Coming to given options. Option A, ${{H}_{2}}$. Hydrogen is a gas and not soluble in water. Because a hydrogen molecule is a non-polar compound and water is a polar molecule. We know that 'like dissolves in like' . So, hydrogen is not going to soluble in water.
-Coming to option B, ${{O}_{2}}$. Oxygen is a polar molecule and dissolves in water called dissolved oxygen. so, oxygen is soluble in water.
-Coming to option C, $S{{O}_{2}}$. Sulphur dioxide is also a polar molecule and dissolves in water and forms sulphurous acid as a product. So, Sulphur dioxide is soluble in water.
${{H}_{2}}O+S{{O}_{2}}\to \underset{Sulphurous\text{ }acid}{\mathop{{{H}_{2}}S{{O}_{3}}}}\,$
-Coming to option D, $C{{O}_{2}}$. Carbon dioxide also reacts with water and forms carbonic acid as a product. The chemical reaction is as follows. So, carbon dioxide is soluble in water.
${{H}_{2}}O+C{{O}_{2}}\to \underset{Carbonic\text{ }acid}{\mathop{{{H}_{2}}C{{O}_{3}}}}\,$
-Therefore Hydrogen is not soluble in water.

So, the correct option is A.

Note: Water is called a universal solvent because of its high polarity. Water tries to make maximum compounds soluble in it. The compounds soluble in water are called polar compounds and compounds not soluble in water are called non-polar compounds.