Question

The hydrogen phosphate of a certain metal has $MHP{O_4}$ formula. The formula of metal chloride is
A.$MCl$
B.${M_2}Cl$
C.$MC{l_3}$
D.$MC{l_2}$

Answer 1

We will find the valency of the hydrogen phosphate ion.so we will accordingly find the appropriate formula of the metal chloride by finding the valency of the metal atom M for the metal chloride compound. We will react the given metal M with chlorine which will form a metal chloride and then find the formula of the metal compound.

Complete step by step answer:
We know that the valency of hydrogen phosphate ion is $- 2$ .so the metal attached to the hydrogen phosphate ion will have a valency of $- 2$
So having a valency of two when this metal combines with chlorine then the reaction taking place is as follows
${M^{2 + }} + 2C{l^ - } \to MC{l_2}$
Here the metal chloride formed, the valency of the metal atom M is two, that is metal M Is divalent so the formula of its chloride is $MC{l_2}$ which holds for any divalent cation whose valency is two.
Therefore we observe that the formula of metal chloride is $MC{l_2}$
Hence the correct answer is option D.

Additional information: The metals having two valencies that are mostly common for alkaline earth metals such as magnesium, calcium, strontium are having the formula of its chloride as $MC{l_2}$ which is true for some d block elements also.

Note:
If the metals are having a valency of two then the formula of the metal chloride will be $MC{l_2}$ Metals such as copper, zinc, cadmium posses this property where the plus-two oxidation state is dominant and the valency of the metal atom is two.
The d block elements having two oxidation generally have the formula of its chloride $MC{l_2}$ .