CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

The freezing point of a solution containing 0.2 g of acetic acid in 20 g of benzene is lowered by 0.45C.. Calculate the degree of association (β) for acetic acid.
Given :
(Kf)Benzene=5.12 K kg mol1

A
0.53
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
0.81
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
0.25
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
0.94
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
Open in App
Solution

The correct option is D 0.94
Weight of acetic acid(w)=0.2 gWeight of benzene(W)=20 g=201000 kgΔTf=0.45C

Let mobs be observed molecular mass of acetic acid

ΔTf=Kf×m

m is molality

mobs=1000×Kf×wW×ΔTf=1000×5.12×0.220×0.45=113.78 g mol1

Theoretical molecular mass of acetic acid =60 g mol1

van't Hoff factor=Theoretical molecular massObserved molecular massi=60113.780.53

2CH3COOH(CH3COOH)2Before associationC 0After association(CCβ) Cβ2

i=CCβ+Cβ2C0.53=1β2
β=0.94

flag
Suggest Corrections
thumbs-up
5
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Van't Hoff Factor
CHEMISTRY
Watch in App
Join BYJU'S Learning Program
CrossIcon