GATE CH format:mcq PYQs & Answers — Page 11

Questions 101–110 of 378. Imported answers require independent review unless marked reviewed.

Consider a steady, fully-developed, uni-directional laminar flow of an incompressible Newtonian fluid (viscosity

) between two infinitely long horizontal plates separated by a distance

as shown in the figure. The flow is driven by the combined action of a pressure gradient and the motion of the bottom plate at

in the negative

direction. Given that

, where

and

are the pressures at two

locations separated by a distance

. The bottom plate has a velocity of magnitude

with respect to the stationary top plate at

. Which one of the following represents the

-component of the fluid velocity vector?

Diagram for Chemical Engineering question 36

Your answerChoose one option.

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

The temperatures of two large parallel plates of equal emissivity are 900 K and 300 K. A reflection radiation shield of low emissivity and negligible conductive resistance is placed parallel between them. The steady-state temperature of the shield, in K, is

Your answerChoose one option.

759

559

659

859

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

Hot oil at 110 °C heats water from 30 °C to 70 °C in a counter-current double-pipe heat exchanger. The flow rates of water and oil are 50 kg min

and 100 kg min

, respectively and their specific heat capacities are 4.2 kJ kg

°C

and 2.0 kJ kg

°C

, respectively. Assume the heat exchanger is at steady state. If the overall heat transfer coefficient is 200 W m

°C

, the heat transfer area in m

Your answerChoose one option.

17.9

1.1

5.2

35.2

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

A solid slab of thickness

is initially at a uniform temperature

. At time

, the temperature of the top surface at

is increased to

, while the bottom surface at

is maintained at

for

. Assume heat transfer occurs only in the

-direction, and all thermal properties of the slab are constant. The time required for the temperature at

to reach 99% of its final steady value is

. If the thickness of the slab is doubled to

, and the time required for the temperature at

to reach 99% of its final steady value is

, then

Your answerChoose one option.

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

A gas stream containing 95 mol% CO

and 5 mol% ethanol is to be scrubbed with pure water in a counter-current, isothermal absorption column to remove ethanol. The desired composition of ethanol in the exit gas stream is 0.5 mol%. The equilibrium mole fraction of ethanol in the gas phase,

, is related to that in the liquid phase,

, as

. Assume CO

is insoluble in water and neglect evaporation of water. If the water flow rate is twice the minimum, the mole fraction of ethanol in the spent water is

Your answerChoose one option.

0.0225

0.0126

0.0428

0.0316

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

Sulfur dioxide (SO

) gas diffuses through a stagnant air-film of thickness 2 mm at 1 bar and 30 °C. The diffusion coefficient of SO

in air is

. The SO

partial pressures at the opposite sides of the film are 0.15 bar and 0.05 bar. The universal gas constant is 8.314 J mol

. Assume ideal gas behavior, the steady-state flux of SO

in mol m

through the air-film is

Your answerChoose one option.

0.077

0.022

0.085

0.057

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

A simple distillation column separates a binary mixture of

and

. The relative volatility of

with respect to

is 2. The steady-state composition of

in the vapour leaving the 1

, 2

and 3

trays in the rectifying section are 94, 90 and 85 mol%, respectively. For ideal trays and constant molar overflow, the reflux-to-distillate ratio is

Your answerChoose one option.

1.9

2.7

1.2

1.1

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

Alumina particles with an initial moisture content of 5 kg per kg dry solid are dried in a batch dryer. For the first two hours, the measured drying rate is constant at 2 kg m

. Thereafter, in the falling-rate period, the rate decreases linearly with the moisture content. The equilibrium moisture content is 0.05 kg per kg dry solid and the drying area of the particles is 0.5 m

per kg dry solid. The total drying time, in h, to reduce the moisture content to half its initial value is

Your answerChoose one option.

4.13

2.55

3.22

5.13

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

A first-order heterogeneous reaction

is carried out using a porous spherical catalyst. Assume isothermal conditions, and that intraphase diffusion controls the reaction rate. At a bulk

concentration of 0.3 mol L

, the observed reaction rate in a 3 mm diameter catalyst particle is 0.2 mol s

catalyst volume. At a bulk

concentration of 0.1 mol L

, the observed reaction rate, in mol s

catalyst volume, in a 6 mm diameter catalyst particle, is

Your answerChoose one option.

0.011

0.033

0.022

0.005

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

A first-order liquid phase reaction

is carried out in two isothermal plug flow reactors (PFRs) of volume 1 m

each, connected in series. The feed flow rate and concentration of

to the first reactor are 10 m

and 1 kmol m

, respectively. At steady-state, the concentration of

at the exit of the second reactor is 0.2 kmol m

. If the two PFRs are replaced by two equal-volume continuously stirred tank reactors (CSTRs) to achieve the same overall steady-state conversion, the volume of each CSTR, in m

, is

Your answerChoose one option.

1.54

3.84

7.28

1.98

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

GATE CH format:mcq PYQs

Question 36

Question 37

Question 38

Question 39

Question 40

Question 41

Question 42

Question 43

Question 44

Question 45