Question

Match List $-I$ with List $-II$:
$$\begin{array}{cccc}& \text{List - I (Name of oxo acid)}& & \text{List - II (Oxidation state of P)}\\ \left(a\right)& \text{Hypophosphorous acid}& \left(i\right)& +5\\ \left(b\right)& \text{Orthophosphoric acid}& \left(ii\right)& +4\\ \left(c\right)& \text{Hypophosphoric acid}& \left(iii\right)& +3\\ \left(d\right)& \text{Orthophosphorous acid}& \left(iv\right)& +2\\ & & \left(v\right)& +1\end{array}$$
Choose the correct answer from the options given below:

• A. $\left(a\right)-\left(iv\right),\left(b\right)-\left(v\right),\left(c\right)-\left(ii\right),\left(d\right)-\left(iii\right)$
• B. $\left(a\right)-\left(v\right),\left(b\right)-\left(iv\right),\left(c\right)-\left(ii\right),\left(d\right)-\left(iii\right)$
• C. $\left(a\right)-\left(v\right),\left(b\right)-\left(i\right),\left(c\right)-\left(ii\right),\left(d\right)-\left(iii\right)$
• D. $\left(a\right)-\left(iv\right),\left(b\right)-\left(i\right),\left(c\right)-\left(ii\right),\left(d\right)-\left(iii\right)$

Answer 1

The correct option is C $\left(a\right)-\left(v\right),\left(b\right)-\left(i\right),\left(c\right)-\left(ii\right),\left(d\right)-\left(iii\right)$

Let, the oxidation state of $P$ be $x$.
We know that,
Oxidation state of $H$ is $+1$ and $O$ is $-2$
Thus, for $H_{3}P{O}_2$
$3\times 1+x+(-2\times 2)=0$
$x=+1$
$\text{Hypophosphorous acid}:\stackrel{+1}{H_{3}P{O}_2}$
Similarly, we can calculate for:
$\text{Orthophosphoric acid}:\stackrel{+5}{H_{3}P{O}_4}$
$\text{Hypophosphoric acid}:\stackrel{+4}{H_4{P}_2{O}_6}$
$\text{Orthophosphorous acid}:\stackrel{+3}{H_{3}P{O}_3}$