If 250 cm ^ 3 of an aqueous solution containing 0 . 73g of a...

For isotonic solution

${i}_{1}{C}_{1} = {i}_{2}{C}_{2}$ {For protein $i = 1$}

${C}_{1} = {C}_{2}$

$⇒ \dfrac{0 . 73 \times 1000}{{M}_{A} \times 250} = \dfrac{1 . 65}{{M}_{B} \times 1}$

$\dfrac{{M}_{A}}{{M}_{B}} = \dfrac{0 . 73 \times 4}{1 . 65} = 1 . 77 = 177 \times {10}^{- 2}$