The volume (in  $\mathrm{m}\mathrm{L}$ ) of $0.1\mathrm{N}\mathrm{N}\mathrm{a}\mathrm{O}\mathrm{H}$  required to neutralise $10\mathrm{m}\mathrm{L}$ of $0.1\mathrm{N}$  phosphinic acid is

Phosphinic acid is hypo phosphorous acid $\left({\mathrm{H}}_3{\mathrm{P}\mathrm{O}}_2\right)$ .

$\mathrm{N}\mathrm{a}\mathrm{O}\mathrm{H}+{\mathrm{H}}_3{\mathrm{P}\mathrm{O}}_2?{\mathrm{N}\mathrm{a}\mathrm{H}}_2{\mathrm{P}\mathrm{O}}_2+{\mathrm{H}}_2\mathrm{O}$

For neutrization

${\left({\mathrm{N}}_1{\mathrm{V}}_1\right)}_{\text{acid}}={\left({\mathrm{N}}_2{\mathrm{V}}_2\right)}_{\text{base}}$

$0.1*10=0.1*{\left({\mathrm{V}}_{\mathrm{m}\mathrm{L}}\right)}_{\mathrm{N}\mathrm{a}\mathrm{O}\mathrm{H}}$