Question

Which is not easily soluble in water?

• A. $H_2$
• B. $O_2$
• C. $S{O}_2$
• D. $C{O}_2$
• E. none of the above

Answer 1

The correct option is A $H_2$

Like dissolve likes. This means that ionic or polar solutes dissolve in polar solvents. Non-polar solutes dissolve in non-polar solvents.

Various gases such as $O_2,N_2,H_2,C{O}_2$ are not very soluble because the gases are essentially non-polar. $H_2$ is almost insoluble (sparingly soluble) and the solubilities of $O_2,S{O}_2$ and $C{O}_2$ are very low.