Question

A salt is formed due to the reaction between an oxy acid containing chlorine and a base containing a monovalent metal of atomic mass $x$. The number of oxygen atoms in one molecule of the acid is more than the corresponding 'ic' acid. Calculate the molecular mass of the salt.

• A. $83.5+\frac{x}{4}$
• B. 99.5 + $x$
• C. 83.5 + $x$
• D. $99.5+\frac{x}{2}$

Answer 1

The correct option is B 99.5 + $x$

An oxy-acid containing chlorine with the name ending with 'ic' acid is chloric acid, $HCl{O}_3$.

The number of oxygen atoms in one molecule of the acid is more than the corresponding 'ic' acid.

Hence, our oxyacid is perchloric acid $HCl{O}_4$.

Let our base be $MOH$ where M is a monovalent metal of atomic mass $x$.

The acid base reaction is :

$HCl{O}_4+MOH\to MCl{O}_4+H_{2}O$

The atomic masses of metal, $Cl$ and $O$ are $xg/mol,35.5g/mol$ and $16g/mol$ respectively.

The molecular mass of the salt $MCl{O}_4$ is $x+35.5+4\left(16\right)=99.5+x$

Hence, the correct answer is option $\text{B}$.