Question

H3PO4 reagent solution in a lab is 85%pure.specific gravity of H3PO4 solution is 1.69.find out the normality of H3PO4.

Answer 1

Technically the normality can't be determined without knowing the reaction involved. The equivalent weight could be molar mass/1, molar mass/2, or molar mass/3 depending upon the replacement of 1, 2, or 3 of the hydrogen atoms. The usual answer is molar mass/3

First I would find the molarity.
1.69g/mL x 1000 mL x 0.85 = ? g H3PO4 in 1 L of solution.
mols H3PO4 = g/molar mass and that will be the molarity.

Then N = 3*M