Question

24. Which of the following compound will have the highest boiling point? A. 9.0 M NaCl B. 1.2 M CaCl2 C. 1,0 MK2SO4 D. 10 M C6H1206 nitia charan?

Answer 1

ΔTb = i*Kb*m

ΔTb is the elevation in boiling point

ΔTb will be maximum when i*m is maximum

so, higher boiling point is for that solution which has higher value of i*m

NaCl dissociates into 1 Na+ and 1 Cl-

So, i = 2

Hence, i*m = 2*9.0 = 18.0

CaCl2 dissociates into 1 Ca2+ and 2 Cl-

So, i = 3

Hence, i*m = 3*1.2 = 3.6

K2SO4 dissociates into 2 K+ and 1 SO42-

So, i = 3

Hence, i*m = 3*1.0 = 3.0

C6H12O6 is non electrolyte and hence it will not dissociate

So, i = 1

Hence, i*m = 1*10.0 = 10.0

Decreasing order of i*m is:

NaCl

C6H12O6

CaCl2

K2SO4

This will be the order of decreasing boiling point

So, compounds from higher to lower boiling point are:

NaCl

C6H12O6

CaCl2

K2SO4

Answer: NaCl