Posted by mona dutta on .
H3PO4 reagent solution in a lab is 85%pure.specific gravity of H3PO4 solution is 1.69.find out the normality of H3PO4.

chemistry 
DrBob222,
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