Question

Identify from the following pair of solutions that exhibits the same osmotic pressure.
[molar mass of urea \(= 60\) g mol\(^{-1}\) and molar mass of glucose \(= 180\) g mol\(^{-1}\)]

• A. \(6\) g/L urea solution and \(18\) g/L glucose solution.
• B. \(12\) g/L urea solution and \(18\) g/L glucose solution.
• C. \(18\) g/L urea solution and \(18\) g/L glucose solution.
• D. \(6\) g/L urea solution and \(6\) g/L glucose solution.

Hint:

Equal molar concentrations of non-electrolytes give equal osmotic pressure.

Answer 1

The Correct Option is A

Step 1: Use \(\pi=CRT\)
Osmotic pressure depends on molarity at the same \(T\). Urea and glucose do not ionise, so only molarity matters.

Step 2: Compute molarities
(A) Urea \(\frac{6}{60}=0.1\) M, glucose \(\frac{18}{180}=0.1\) M. Equal.
(B) \(0.2\) M vs \(0.1\) M. Not equal.
(C) \(0.3\) M vs \(0.1\) M. Not equal.
(D) \(0.1\) M vs \(0.033\) M. Not equal.

Final Answer:
Both solutions in (A) are \(0.1\) M, option (A). \[ \boxed{\text{(A)}} \]