Question

Oxidation number of calcium in calcium phosphate :

• A. $1^{+}$
• B. $1^{-}$
• C. $0$
• D. $2^{+}$
• E. $3^{+}$

Answer 1

Answer: (D)

$2^{+}$

As $Ca$ is the Alkaline earth metal hence it has electrovalency to be +2, only. Hence, its oxidation state , can not change, from 2.
$C{a}_3(P{O}_4{)}_2$:
As charge of phosphate $\left(P{O}_4^{3-}\right)$ group is $-2$ , Let the oxidation state of $Ca$ be $x$. and whole unit is neutral.
$3\times x+2\times (-3)=0$
$3x-6=0$
$3x=+6$
$x=\frac{+6}{3}=+2$
So , $Ca$ has $+2$ oxidation state.