Solutions Question 72

Question: The freezing point of one molal $ NaCl $ solution assuming $ NaCl $ to be 100% dissociated in water is (molal depression constant = 1.86) [CPMT 1985; BHU 1981; MP PMT 1997; UPSEAT 2001]

Options:

A) $ -{{1.86}^{o}}C $

B) $ -{{3.72}^{o}}C $

C) $ +{{1.86}^{o}}C $

D) $ +{{3.72}^{o}}C $

Show Answer

Answer:

Correct Answer: B

Solution:

For $ NaCl $

$ i=2 $

$ \Delta T_{f}=2K_{f}m=2\times 1.86\times 1=3.72 $

$ T_{s}=T-\Delta T_{f}=0-3.72=-3.72{}^\circ C $



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