Question

Molal freezing point depression constant for water is 18.6 K mol per 100 g. It can be written as:​

Answer 1

Answer:

Correct option is

B

−0.372  

o

C

Depression in freezing point is given by

ΔT  

f

​

=i×K  

f

​

×m

ΔT  

f

​

=T  

f

o

​

−T  

f

​

 

i= Vant hoff factor =1 (for non electrolyte)

K  

f

​

=1.86K/m

m= Molality

ΔT  

f

​

=i×K  

f

​

×  

weight of solvent in kg

moles of solute

​

 

Moles of solution (urea) =0.02

Molar mass of solute (urea) =60g/mol

Weight of solvent (water) =100g=0.1kg

(T  

f

0

​

−T  

f

​

)=1×1.86×  

0.1kg

0.02

(0−T  

f

​

)  

o

C=0.372

T  

f

=−0.372  

o

C

Explanation: