Question

$A{B}_4^{-}+C^{+2}\to C^{+3}+A^{+2}$
If the Oxidation number of B is -2. Choose the true statement for the above change -

• A. O.N. of A decreases by -5
• B. O.N. of C decreases by +1
• C. O.N. of A decreases by +5 and that of C increases by +1
• D. O.N. of A decreases by +5 and that of C decreases by +1

Answer 1

The correct option is C O.N. of A decreases by +5 and that of C increases by +1

$A{B}_4^{-}+C^{+2}\to C^{+3}+A^{+2}$

From the above equation and the oxidation number of, B we can calculate the O.N of $A$ as follows.

$x+4(-2)=-1$
$x=+7$

The oxidation number of $A$ in the L.H.S of the equation is $+7$ and in the R.H.S it becomes $+2$.
Therefore there is a decrease in the oxidation satate of $A$ by $+5$

Similarly the O.N of $C$ in the L.H.S is $+2$ and in the R.H.S is $+3$.
Therefore there is an increase in th O.N of $C$ by $+1$