Question

Assuming the salts to be unionised in solution, which of the following has highest osmotic pressure?

• A. $1\%CsCl$
• B. $1\%RbCl$
• C. $1\%KCl$
• D. $1\%NaCl$

Answer 1

The correct option is D $1\%NaCl$

Since, all salts are unionised in solution means vant Haff factor $i$ is same for all.

$\therefore \pi =CRT$

1% of salt means 1 gram of solute dissolved in 100 gram of solvent

we have,

$\pi =CRT=\frac{givenweight}{molecularweight\times volume}RT$

since, molecular weight is inversely proportional to osmotic pressure,

since, NaCl have lowest molecular mass and hence highest osmotic pressure.

Option (D) is correct.