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#molar mass

90 public questions tagged with this topic.

The vapor pressure of pure water is 25 mm Hg at a certain temperature. A solution with a non-volatile solute has a vapor

(p⁰ - p/p⁰) = xsolute . (25 - 23/25) = 0.08 . Moles of water = (180/18) = 10 . xsolute = (nsolute/nsolute + 10) = 0.08 . nsolute = 0.08 (nsolute + 10) , nsolute - 0.08 nsolute = 0.8 , 0.92 nsolute = 0.8 , nsolute ≈ 0.8696 . Mass = 0.8696 × 60 ≈ 52.18 g .

Ref: NCERT Class 12 Chemistry > Chapter 1: Solutions > Topic: Vapour Pressure and Raoult's Law - Ideal and Non-ideal Solutions

The vapor pressure of pure water is 28 mm Hg at a certain temperature. A solution with a non-volatile solute has a vapor

(p⁰ - p/p⁰) = xsolute . (28 - 26.6/28) = (1.4/28) = 0.05 . Moles of water = (360/18) = 20 . xsolute = (nsolute/nsolute + 20) = 0.05 . nsolute = 0.05 (nsolute + 20) , 0.95 nsolute = 1 , nsolute ≈ 1.0526 . Mass = 1.0526 × 50 ≈ 52.63 g .

Ref: NCERT Class 12 Chemistry > Chapter 1: Solutions > Topic: Vapour Pressure and Raoult's Law - Ideal and Non-ideal Solutions

A solution is prepared with 46 g of ethanol (molar mass = 46 g/mol) and 54 g of water. If the mole fraction of ethanol b

Initial moles of ethanol = (46/46) = 1 . Moles of water = (54/18) = 3 . Let additional moles of ethanol = x . New mole fraction = (1 + x/1 + x + 3) = 0.4 . 1 + x = 0.4 (4 + x) , 1 + x = 1.6 + 0.4x , 0.6x = 0.6 , x = 1 . Mass added = 1 × 46 = 46 g .

Ref: NCERT Class 12 Chemistry > Chapter 1: Solutions > Topic: Colligative Properties - Relative Lowering and Elevation of Boiling Point