The Total solution for NCERT class 6-12
Boiling point of water at 750 mmHg is 99.63°C. How much sucrose is to be added to 500 g of water such that itboils at 100°C. Molal elevation constant for water is 0.52 K kg mol−1.
Here, elevation of boiling pointΔTb = (100 + 273) − (99.63 + 273)
= 0.37 K
Mass of water, wl =500 g
Molar mass of sucrose (C12H22O11), M2 =11 × 12 + 22 × 1 + 11 × 16
= 342 g mol−1
Molal elevation constant, Kb =0.52 K kg mol−1
We know that: