Question

Solution of 'A' containing 1.73 g of it in 100 cm³ of water is found to be isotonic with a 3.42% (w/v) solution of sucrose. The molecular weight of A is ______. (At. mass C = 12, H = 1, 0 = 16)

Options

• 68

• 342

• 180

• 173

Answer 1

Solution of 'A' containing 1.73 g of it in 100 cm³ of water is found to be isotonic with a 3.42% (w/v) solution of sucrose. The molecular weight of A is 173.

Explanation:

`pi_"A" = (pi)_"sucrose"`

`("CRT")_"A" = ("CRT")_"sucrose"`; R & T are constant.

`1.73/"M"_"A" xx 1000/100 = 3.42/342 xx 1000/100`

M_A = 1.73 × 100 = 173