Chemical - Set 1 - Questions PDF
Chemical - Set 1 - Questions PDF
Chemical - Set 1 - Questions PDF
3. Which one of the following is having the lowest value of fouling factor?
A. Lake river
B. Distilled water
C. Transformers
D. Lubricating oil
4. For turbulent flow over a flat plate, the average value of Nusselt number
is prescribed by the relation
Nu = 0.664 (Re) 0.5 (Pr) 0.33
Which of the following is then a false statement?
The average heat transfer coefficient increases as:
A. 1/5 power of plate length
B. 2/3 power of thermal conductivity
C. 1/3 power of specific heat
D. 4/5 power of a free stream velocity
6. During test-run, air flows at 215 m/s velocity and 25 degree Celsius
temperature past a smooth thin model airfoil which can be idealized as a
flat plate. If the chord length of the airfoil is 15 cm, find drag per unit width.
The relevant physical properties of air are
p = 1.82 kg/m3
v = 15.53 * 10 -6 m2/s:
A. 25.42 N per unit width
B. 35.42 N per unit width
C. 45.42 N per unit width
D. 55.42 N per unit width
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7. The equilibrium concentrations in the gas and the liquid phases, in mole
fraction, give rise to a curve known as
A. Equilibrium distribution curve
B. Equilibrium concentration curve
C. Differential distribution curve
D. Differential concentration curve
9. If the distillate has a composition of azeotrope and the residue has rich
phase of one component. Then the azeotrope mixture is a
A. Maximum-boiling mixture
B. Minimum boiling mixture
C. Constant boiling mixture
D. Differential boiling mixture
10. A certain material was dried under constant drying condition and it was
found that 2 hour are required to reduce the free moisture concentration
form 20% to 10% how much longer would be required to reduce the free
moisture to 4%? Assume that no constant rate period is encountered.
A. 2hrs
B. 2.4hrs
C. 2.8hrs
D. 3.2hrs
11. The time constant of a unity gain, first order plus time delay process is 5
min. if the phase lag at a frequency of 0.2 red/min is 60 degrees, then the
dead time is (mintes)
A. 5π/12
B. π/6
C. π/12
D. π/3
12. A control system is unstable, if the open loop frequency response
exhibits an amplitude ratio exceeding unity at the crossover frequency.
This is ______criterion
A. Bode stability
B. Nyquist
C. Routh stability
D. None of these
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13. Wet natural gas contains substantial amount of –––––––––
A. ethane
B. propane
C. butane
D. all of the above
19. The gas phase reaction 2A + B ----->C is carried out in a PFR. The feed
is equal molar in A and B and the entering temperature is 500K and the
entering pressure is 16.4 atm. If the exit conversion is X, then the exit
concentration of B (in mol/dm3) is
A. CB = 0.4(1-X)/(1-0.5X)
B. CB = 0.4(1-X)/(1-1.5X)
C. CB = 0.2
D. CB = 0.4(1-0.5X)/(1-X)
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20. Potassium carbonate is not prepared by the Solvy process because
A. potassium bicarbonate is unstable
B. potassium bicarbonate is soluble is water
C. potassium bicarbonate is soluble in ammonium chloride and potassium
chloride solutions
D. potassium bicarbonate does not decompose on heating
22. 1.5 Kg of this gas occupying a volume of 0.06 m3 at 5.6 MPa expands
isentropically until the temperature is 240 oC. if a= 0.946, b= 0.662 and k=
10-4, the work done in the expantion is
A. 104 kJ
B. 204 kJ
C. 304 kJ
D. 404 kJ
24. Air at 600 K flows with 3 kg/s into a heat exchanger and out at 100°C. How
much (kg/s) water coming in at 100 kPa, 20°C can the air heat to the boiling
point?
E. 0.37 kg/s
F. 0.17 kg/s
G. 0.27 kg/s
H. 0.57 kg/s
25. A hot metal piece is cooled rapidly to 25°C, removing 1000 kJ from the
metal. Calculate the change of entropy if energy is absorbed by
vaporizing liquid nitrogen at 101.3 kPa pressure.
A. 9.929 kJ/K
B. 10.929 kJ/K
C. 11.929 kJ/K
D. 12.929 kJ/K