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.$83.5 + \dfrac{x}{4}$
B.$99.5 + x$
C. $83.5 + x$
D. $99.5 + \dfrac{x}{2}$

Answer 1

Hint An oxy-acid containing chlorine with the name ending with 'ic' acid is chloric acid, $HCl{O_3}$. With an addition of an oxygen atom it becomes $HCl{O_4}$.The molecular mass of the salt formed is a number equal to the sum of the atomic masses of the atoms in a molecule.

Complete answer:
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 . The reaction when oxy-acid of chlorine is reacted with a base.
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 sum of all the atomic masses of all the metals and compounds involved in the reaction are $MCl{O_4}$ , $Cl$ , ${O_2}$.
The atomic masses of the metals are $x\,g/mol$ , $35.5\,g/mol$ , $16\,g/mol$
The molecular mass of the salt $MCl{O_4}$ is $x + 35.5 + 16$
i.e $99.5g + x$

**Therefore the correct option is $99.5g + x$. Hence the correct option is option (B).

Note:**

The molecular mass is the sum of the masses of the atoms in a molecule.Covalent compounds are formed as the result of a reaction between two nonmetals. An oxoacid is an acid that contains oxygen, contains at least one other element, has at least one hydrogen atom bonded to oxygen, forms an ion by the loss of one or more protons in solution.