Question

Mohr's indicator is 5g/100ml of K2CrO4 in water. What is the concentration of CrO4^2- in the indicator? (in mol/L)

Answer 1

5g/100 = (K2CrO4)

mols K2CrO4 = grams/molar mass = approx 0.026 but you should do it more accurately.
K2CrO4 --> 2K^+ + CrO4^2-
So (K2CrO4) = 0.026 mol/0.1L = 0.26 M
(K^+) = 2*0.26 = ?M
(CrO4^2-) = 0.26M