Question

normality of 0.3 m phosphorous acid

Answer 1

normality = n×molarity
n of phosphorus acid is 3
so normality = 3×molarity
3×0.3
0.9

Answer 2

Normality of 0.3 m phosphorous acid is 0.6 N.

The normality is given by the equation:

$Normality =\text { Molarity } \times n . f.$

Where n.f. is the n-factor i.e., the acidity of a base or the basicity of an acid.

Here we know that the Molarity = 0.3.

The acid given is Phosphorous Acid whose n.f. factor is 2. Phosphorus acid has a basicity of 2.

This is because $\mathrm{H}_{3} \mathrm{PO}_{3}$ can denote two $OH^{-}$ ions or it contains 2 replaceable $H^{+}$  ions.

So, Normality $=\text { Molarity } \times \text { n.} f .=0.3 \times 2=0.6 \mathrm{N}$.