Why is the elevation in boiling point of water different in the following solutions?
i) 0.1 molar NaCl solution
ii) 0.1 molar sugar solution
i) 0.1 molar NaCl solution
ii) 0.1 molar sugar solution
Answer: NaCl gives twice as many particles as sugar at the same molarity, so its ΔT_b is about double — the elevations differ.
Solution
Elevation of boiling point depends only on the number of solute particles.
0.1 M NaCl dissociates into Na and Cl, giving about 0.2 M particles; 0.1 M sugar stays molecular, giving 0.1 M particles.
The NaCl solution therefore shows nearly twice the elevation shown by the sugar solution.
0.1 M NaCl dissociates into Na and Cl, giving about 0.2 M particles; 0.1 M sugar stays molecular, giving 0.1 M particles.
The NaCl solution therefore shows nearly twice the elevation shown by the sugar solution.
CBSE Class 12 Board · 2005 · Delhi Compartment; also All India 2004 Compartment · Subjective