Chemical Engineering Basics MCQs

Question 1

Pick out the wrong statement:

Accepted Answer

Pure copper is highly susceptible to stress corrosion

Answer

Soft water is more corrosive than that carrying calcium salts

Answer

The corrosion of brass condenser tubes handling brine solution is also termed as 'dezincification'

Answer

Non-annealed brass is highly susceptible to season cracking (i.e., inter-crystal corrosion due to internal stresses)

Question 2

Lap joints are preferred over butt joints in soldering/brazing, because these joints are

Accepted Answer

The lap joints are easily made

Answer

Weaker in tension but stronger in shear

Answer

Weaker in shear but stronger in tension

Answer

Stronger in both shear and tension

Question 3

α-rays are

Accepted Answer

Positively charged

Answer

Negatively charged

Answer

Neutral

Answer

Same as X-rays

Question 4

In a totally irreversible isothermal expansion process for an ideal gas, ΔE = 0, ΔH = 0. Then ΔQ and ΔS will be

Accepted Answer

ΔQ = 0 , ΔS = +ve

Answer

ΔQ = 0, ΔS=0

Answer

ΔQ = 0, ΔS = -ve

Answer

ΔQ = +ve , ΔS= +ve

Question 5

While the recrystallisation temperature for pure metals is 0.3 T m , the same for alloys is equal to __________ × T m (where, T m Melting temperature).

Accepted Answer

0.7

Answer

0.25

Answer

0.45

Answer

0.95

Question 6

The refrigerant freon-12 is chemically

Accepted Answer

CCl 2 F 2

Answer

CCl 3 F

Answer

CClF 3

Answer

CCl 4 F

Question 7

What is the critical radius of insulation (cms) for a metallic cylinder, if the convective heat transfer co-efficient with the ambient atmosphere is 5 W/m 2 .°K? Thermal conductivity of metal and insulation material are 40 and 0.1 W/m.°K respectively.

Accepted Answer

2

Answer

5

Answer

10

Answer

20

Question 8

The fugacity of liquid water at 298 K is approximately 3171 P a . Considering the ideal heat of vaporisation as 43723 J/gm mole, its fugacity at 300 K would be

Accepted Answer

3567 P a

Answer

3171 P a

Answer

1.01 × 10 5 P a

Answer

5000 P a

Question 9

For which pair of the fuel gases, calorific value (C.V.) of one fuel is almost double that of the other on volume basis (i.e., kcal/Nm 3 ) while the C.V. is same on weight basis (i.e., kcal/kg)?

Accepted Answer

B.F. gas and coke oven gas

Answer

Propane and acetylene

Answer

Propane and LPG

Answer

Sewage gas and gobar gas