Question

Solution A,B,C and D are respectively 0.1M Glucose, 0.05M NaCl, 0.05M $BaC{l}_2$ and 0.1M $Al{F}_3$. which one of the following pairs is isotonic?

• A. A&C
• B. B&C
• C. A&B
• D. A&D

Answer 1

Answer: (C)

A&B

The solutions A (0.1 M glucose) and B (0.05 M $NaCl$) are isotonic.

They have the same osmotic pressure. The product of molar concentration and the number of ions obtained on dissociation of 1 molecule of solute is the same for both solutions. Glucose is non-electrolyte and does not dissociate. Hence the product will be, $0.1\times 0.1$ = 0.1

One molecule of $NaCl$ dissociates to give two ions,

Hence the product is $0.05\times 2$ $=0.1$

C is the correct option.