Q15 / 150 · MHT CET 2026 (13 April Shift 2) · Chemistry
A solution is prepared by dissolving $68$ g sucrose in $1$ kg water. Calculate the vapour pressure of solution at $298$ K. [vapour pressure of water at $298$ K = $18$ mm of Hg & mole fraction of solvent = $0.9964$]
- Correct answerA$17.93$ mm Hg
- B$17.80$ mm Hg
- C$17.76$ mm Hg
- D$17.68$ mm Hg
Solution
According to Raoult's law, the vapour pressure of a solution containing a non-volatile solute is given by:
$P_{s} = P^{\circ} \times X_{\text{solvent}}$
Given:
$P^{\circ} = 18$ mm Hg
$X_{\text{solvent}} = 0.9964$
Substituting the values:
$P_{s} = 18 \times 0.9964 = 17.9352$ mm Hg
Rounding off, we get $17.93$ mm Hg.
Answer: $17.93$ mm Hg
$P_{s} = P^{\circ} \times X_{\text{solvent}}$
Given:
$P^{\circ} = 18$ mm Hg
$X_{\text{solvent}} = 0.9964$
Substituting the values:
$P_{s} = 18 \times 0.9964 = 17.9352$ mm Hg
Rounding off, we get $17.93$ mm Hg.
Answer: $17.93$ mm Hg
Hence, the correct answer is option: 'A'.