Dear student,

Your question is incomplete, because you have not provided the volume of solution. And without volume of solution, normality of 41g H3PO3 can't be found out.

But still here let me show you that how you will proceed or approach this question.

Phosphorous acid has a n-factor of 2.

Now, equivalent weight of phosphorus acid =  ( molar mass of H3PO3 ) / n-factor

So, equivalent weight ( E ) = 82/2 = 41

Now, normality is defined as - number of equivalents of solute present in 1000ml of solution.

N = { W (in g) × 1000 } / E × volume of solution ( in ml )

So, as you can see, without the volume of solution, your cannot find normality.