The fraction of phenol dimerised in benzene if 20 g of phenol in 1 kg benzene exhibits a freezing point depression of 0.69 K. (Kf benzene = 5.12 ), (MW phenol = 94). What is the value of Van’t Hoff for (i) in this reaction?

Question

The fraction of phenol dimerised in benzene if 20 g of phenol in 1 kg benzene exhibits a freezing point depression of 0.69 K. (Kf benzene = 5.12 ), (MW phenol = 94). What is the value of Van’t Hoff for (i) in this reaction? (A) 0.63 (B) 0.37 (C) 0.46 (D) 0.64

Tardigrade Admin · Accepted Answer

Δ Tf=i. kb. m 0.69=i× (5.12× 20 × 1000/94× 1000) ⇒ i=0.63

Q. The fraction of phenol dimerised in benzene if $20 g$ of phenol in $1 k g$ benzene exhibits a freezing point depression of $0.69 K$ . $(K_{f}$ benzene = 5.12 ), (MW phenol = 94). What is the value of Van’t Hoff for (i) in this reaction?

$0.63$

$0.37$

$0.46$

$0.64$

$Δ T_{f} = i . k_{b} . m$
$0.69 = i \times \frac{5.12 \times 20 \times 1000}{94 \times 1000}$
$\Rightarrow i = 0.63$

Q. The fraction of phenol dimerised in benzene if 20g of phenol in 1kg benzene exhibits a freezing point depression of 0.69K. (Kf​ benzene = 5.12 ), (MW phenol = 94). What is the value of Van’t Hoff for (i) in this reaction?

0.63

0.37

0.46

0.64