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Solutions - Intext Questions and Answer - class 12 chemistry


Solution of NCERT In Text Questions-2.10

Question - 2.10 - Boiling point of water at 750 mm Hg is 99.63°C. How much sucrose is to be added to 500 g of water such that it boils at 100°C.

Solution:

Given,

Elevation of boiling point

Solutions class 12 chemistry - NCERT In Text Solution55

Mass of water (W A) = 500 g

Molar mass (M B) of sucrose (C 12H22 O11 ) = 12 x 12 + 1 x 22 + 16 x 11 = 342 g mol – 1

Molal constant for water (Kb ) = 0.52 K kg mol – 1

Therefore, W B = ?

We know that,

Solutions class 12 chemistry - NCERT In Text Solution56

Thus, 121.67 g of sucrose to be added.