Question

The valency of sulphate radical is equal to the valency of ……….. radical.
A.Phosphate
B.Hydrogen phosphate
C.Dihydrogen phosphate
D.Phosphide

Answer 1

Hint: Write the chemical formula of radicals given and compare it with the chemical formula of sulphate radical to know valency.

Complete step by step answer:
Let's consider sulphate radical, the chemical formula is given by ${ { SO }_{ 4 } }^{ 2- }$. Here we can see there is a -2 charge on ${ { SO }_{ 4 } }$, which means it has -2 valency.
Now look at the option (a), phosphate can be written as ${ { PO }_{ 4 } }^{ 3- }$. There is -3 charge on ${ { PO }_{ 4 } }$, that means it has -3 valency.
In option (b), hydrogen phosphate can be written as ${ { { HPO }_{ 4 } } }^{ 2- }$. There is -2 charge on ${ { { HPO }_{ 4 } } }$, which means it has -2 valency.
In option (c), dihydrogen phosphate can be written as ${ { { { H }_{ 2 }PO }_{ 4 } } }^{ 1- }$. There is -1 charge on ${ { { { H }_{ 2 }PO }_{ 4 } } }$, that means it has -1 valency.
In option (d), phosphide can be written as ${ P }^{ 3- }$. There is -3 charge on P, that means it has -3 valency.
So among all these options, hydrogen phosphate has the same valency as sulphate.
Correct option is B

Note:
Valency of non-hydrogen containing compound - Aluminum sulfate has the formula ${ { Al }_{ 2 }{ (SO }_{ 4 }) }_{ 3 }$ and it is a non-hydrogen containing compound. Aluminum has a valency of 3+. Aluminium makes ions with a positive charge, which is why the sulfate ion has a negative charge, and that makes the sulfate radical have a 2- valency.