Question

Arrange the following solutions in increasing order of their osmotic pressures
(i) $34.2g/litre$ sucrose
(ii) $60g/litre$ of urea
(iii) $90g/litre$ of glucose
(iv) $58.5g/litre$ of sodium chloride

• A. (i) < (iii) < (ii) < (iv)
• B. (ii) < (i) < (iv) < (ii)
• C. (i) < (iii) < (iv) < (ii)
• D. (ii) < (iv) < (i) < (iii)

Answer 1

The correct option is A (i) < (iii) < (ii) < (iv)

(a) : Sucrose Urea Glucose NaCl

Strength $\left(g{L}^{-1}\right)$: $34.2$ $60$ $90$ $58.5$

Molarity: $\frac{34.2}{342}=0.1$ $\frac{60}{60}=1$ $\frac{90}{180}=0.5$ $\frac{58.5}{58.5}=1$

$i:$ $1$ $1$ $1$ $2$

We know, $\pi =iCRT$

Thus, Osmotic pressure of these solutions will lie in following sequence:

Sucrose<Glucose<Urea<NaCl

(i) (iii) (ii) (iv)