(a) Derive a relationship between molality & molarity of a solution in which w g of solute of molar mass M g/mol is dissolved in W g solvent & density of resulting solution = 'd' g/ml.
(b) Calculate molality of 1.2 M `H_2SO_4` solution ? If its `rho` = 1.4 g/mL

Explanation

(a) Say 1 L solution taken,
mass of 1 lit solution = (1000 d) g
moles of solute = (molarity)
mass of solute = (molarity) `xx` m
mass of solvent = W = 1000 d – (molarity) `xx` m
`:.` `"molarity"=(("molarity")xx1000)/(1000d-"molarity"xxM.Wt)`
[Where no.of moles of solute = molarity]
(b) `"Molarity"=(1.2xx1000)/(1000xx1.4-1.2xx98)=0.936`