22-03-09 Past IIT JEE Questions Chemistry

Q1)
Rate of Physisorbtion increases with
A) Decrease in Temperature
B) Inc in Temp
C) Dec in pressure
D) Dec in surface area

Q2
Lyophilic sols are

A) Irreversible sols
B) Prepared from inorganic compounds
C) coagulated by adding electrolytes
D) Self stabilizing

Q3)
20% of surface sites are occupied by N2 molecules. The density of surace site is 6.023x1014 cm-2. and the total surace area is 1000cm2.
The catalyst is heated to 300K while N2 completely desorbed into a pressure of 0.001 atm and volume of 2.46 cm3. Find the number active sites occupied by each N2 molecule.

6 Answers

1
# ·

1] increases with decrease in temperature as forces involved are wvander waal,s forces.

1
Optimus Prime ·

Q.2 lyophilic sols are solvent seeking , they are reversible and stable hence the answer is D

1
Optimus Prime ·

q.3

number of active sites per unit area = 6.023x1014 cm-2

surface area of the metal=100cm2

therefore number of active sites= 6.023x1014x1000=6.023x1017

number of active sites adsorbed by N2 molecules = 20/100x6.023x1017=1.2046x1017

nmber of N2 molecules = PVNav/RT = [0.001x2.46x10-3/0.0821x300] x 6.023x1023

= 6.015 x1016

therefor number of active sites adsorbed by each N2 molecule =1.2046x1017/6.015x1016≈2

answer=2

1
Optimus Prime ·

Q.1 heat of absorption is low . Low temperature is favourable and increases with decrease in temperature, hence option A

1
Optimus Prime ·

what are the corrcet answers

21
tapanmast Vora ·

OH I NEVER SAW THIS [2] [17]

THNX SIR!!!!!!!! [1]

@sir : Oh k... so this is da level and knidof Questns v can expext on the 12th [12]

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