1

JEE Advanced 2014 Paper 2 Offline

MCQ (Single Correct Answer)

X and Y are two volatile liquids with molar weights of 10 g mol$$-$$1 and 40 g mol$$-$$1, respectively. Two cotton plugs, one soaked in X and the other soaked in Y, are simultaneously placed at the ends of a tube of length L = 24 cm, as shown in the figure. The tube is filled with an inert gas at 1 atmosphere pressure and a temperature of 300 K. Vapours of X and Y react to form a product which is first observed at a distance d cm from the plug soaked in X. Take X and Y to have equal molecular diameters and assume ideal behaviour for the inert gas and the two vapours.

The experimental value of d is found to be smaller than the estimate obtained using Graham's law. This is due to

A
larger mean free path for X as compared to that of Y.
B
larger mean free path for Y as compared to that of X.
C
increased collision frequency of Y with the inert gas as compared to that of X with the inert gas.
D
increased collision frequency of X with the inert gas as compared to that of Y with the inert gas.

Explanation

Collision frequency of X is greater than Y.

2

JEE Advanced 2014 Paper 2 Offline

MCQ (Single Correct Answer)

X and Y are two volatile liquids with molar weights of 10 g mol$$-$$1 and 40 g mol$$-$$1, respectively. Two cotton plugs, one soaked in X and the other soaked in Y, are simultaneously placed at the ends of a tube of length L = 24 cm, as shown in the figure. The tube is filled with an inert gas at 1 atmosphere pressure and a temperature of 300 K. Vapours of X and Y react to form a product which is first observed at a distance d cm from the plug soaked in X. Take X and Y to have equal molecular diameters and assume ideal behaviour for the inert gas and the two vapours.

The value of d in cm (shown in the figure), as estimated from Graham's law, is
A
8
B
12
C
16
D
20

Explanation

Using Graham's law of diffusion, we have that for identical conditions, rate of diffusion varies inversely with square root of mass of the gases. So,

$${x \over {24 - x}} = {\left( {{{40} \over {10}}} \right)^{1/2}} \Rightarrow x = 16$$

3

JEE Advanced 2014 Paper 2 Offline

MCQ (Single Correct Answer)
For the elementary reaction M $$\to$$ N, the rate of disappearance of M increases by a factor of 8 upon doubling the concentration of M. The order of the reaction with respect to M is
A
4
B
3
C
2
D
1
4

JEE Advanced 2013 Paper 1 Offline

MCQ (Single Correct Answer)

In the reaction, P + Q $$\to$$ R + S, the time taken for 75% reaction of P is twice the time taken for 50% reaction of P. The concentration of Q varies with reaction time as shown in the figure. The overall order of the reaction is

A
2
B
3
C
0
D
1

Explanation

This is a first-order reaction because t75% = 2 $$\times$$ t50%. The graph shows that the order with respect to Q is 0, so we can write the rate expression as

Rate = k[P]1[Q]0

Joint Entrance Examination

JEE Main JEE Advanced WB JEE

Graduate Aptitude Test in Engineering

GATE CSE GATE ECE GATE EE GATE ME GATE CE GATE PI GATE IN

Medical

NEET

CBSE

Class 12