Question

How to prepare M/40 solution of mohr's salt and using this to determine the molarity and strength of given KMno4 solution

Answer 1

Molar mass of Mohr's Salt FeSO4. (NH4)2SO4 .6 H2O = 392 g / mol

equivalent wt. = molecular mass / n = 392 / 1 = 392

1 M of KMnO4 solution will need = 392 g / mol

M/ 40 KMnO4 solution would be = 392 / 40 = 9.8

Number of moles of salt = mass / molecular mass = 9.8 / 392 = 0.025 moles

Molarity of solution = no. of moles/ volume = 0.025 / 1

Strength of KMnO4 = 0.025 x 158 = 3.95 g / mol