JEE Main 2026 · 6 Apr · Shift 1 · Chemistry Q56

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ChemistrySingle correct+4 / -1Question 56 of 75

When 0.25 moles of a non-volatile, non-ionizable solute was dissolved in 1 mole of a solvent the vapor pressure of solution was $x$ % of vapor pressure of pure solvent. What is $x$ %?

50%

60%

70%

80%

Answer and worked solution

Official answer: D

Raoult's law. The relative vapour pressure equals the solvent's mole fraction:
$\frac{p}{p^\circ}=\frac1{1+0.25}=0.8,$
so $x=80\%$ .

(D)

Topics:Raoult's law and vapour pressure

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JEE Main 2026 · 6 Apr · Shift 1, Chemistry question 56