Question

Which of the following statements explains why oil has a greater viscosity than water?

1. Oil molecules always move slower than water molecules 2. Oil molecules have more space in between them than water molecules 3. Oil molecules have a more complicated shape than water molecules 4. Oil molecules are less dense than water molecules

Which of the following statements is incorrect?

1. A catalyst does not alter the state of equilibrium in a chemical reaction 2. A catalyst remains unchanged at the end of a chemical reaction 3. A catalyst is highly specific in its action 4. A catalyst initiates a reaction.

White phosphorous is stored under water, because	1. it does not react with water 2. it is poisonous 3. it is unstable 4. its kindling temperature in dry air is very low
With increase in the number of shell passes, the value of FT(Temperature correction factor)	1. remains same 2. remains same, only if the number of tube passes does not change. 3. decreases 4. increases
Use of baffles in agitators help in minimizing the __________ tendency.	1. both swirling and vortex 2. vortex 3. swirling 4. neither swirling nor vortex
In liquid-liquid equilibrium studies, a system is called type II if	1. the A-C pair is immiscible 2. the B-C and A-B pairs are partly miscible 3. the B-C pair is completely miscible 4. A-B miscible
The cross over frequency of the process which is having the transfer function of G(s) = 5/(2s+1)4	1. 20 2. 0.1 3. 0.5 4. 0.05
Molecularity of an elementary reaction P + Q = R + S is	1. 1 2. 2 3. 3 4. 4
Cavitation in centrifugal pumps is caused by	1. High fluid velocity at suction 2.low barometric pressure 3.low suction pressure 4.high suction pressure
Cavitation in centrifugal pumps may be eliminated by maintaining	1.suction pressure higher than vapor pressure of the liquid at the suction temperature. 2. suction pressure sufficiently lower than vapor pressure of the liquid at the suction temperature. 3.liquid velocity at the suction less than 0.3 ft/s 4.suction pressure less than 1 atm.
consider distribution of the solute C in two partially miscible solvents A(carrier) and B(solvent). What is the selectivity of separation at the plait point?	1. 1 2. very large 3. Zero 4. less
Cooling water fouling factors vary in the range of 0.001 to 0.003. What is the SI unit?	1. (kcal/hr. m. °C)-1 2. (W/m2.°K)-1 3. (BTU/hr.ft2. °F)-1 4. (kcal/hr.m2.°C)-1
Industrially, the process of sedimentation is conducted on a large scale in equipment called	1.sorting classifiers 2.cyclones 3.thickeners 4.filters
The Schedule number is an indication of	1.material density 2.pipe wall thickness 3.pipe size 4.pipe roughness

Answer all the MCQs correctly with proper explanation.

Answer 1

Q1. Ans: Oil molecules have a more complicated shape than water molecules.	Oil has large linear molecules which results in strong intermolecular force of attraction and more internal friction.
Q2. Ans: A catalyst initiates a reaction.	A catalyst can accelerate the rate of reaction but it can't initiate the reaction. All catalysts are specific for the reactant. A certain catalyst can react with a particular reactant only. A catalyst increases the speed of the reaction but it can't change the nature and type of product.
Q3. Ans: its kindling temperature in dry air is very low	White phosphorus is very reactive compared to all other allotropes of phosphorus. It reacts immediately as it comes in contact with the atmospheric air.
Q4. Ans: remains same, only if the number of tube passes does not change.	F correction factor depends on the geometry of the heat exchanger and the inlet and outlet temperatures of the hot and cold fluid streams.
Q5. Ans: both swirling and vortex	Baffles are attached to the interior of the tank proturbing outwards in a mixing tank which prevents the vortex formation and swirling of fluid.
Q6. Ans: the B-C and A-B pairs are partly miscible	In Type II System with 3 components A, B and C, only A and C are completely soluble, while the pairs A-B and B-C have limited solubility at equilibrium.
Q7. Ans 0.5	Here time constant t = 2, and cross over frequency w = 1/t = 0.5
Q8. Ans 2	The molecularity of an elementary reaction is equal to the sum of the stiochiometric cofficients of reactants.