Chemical Reaction Engineering MCQs

Question 1

The exit age distribution of fluid leaving a vessel is used to know the

Accepted Answer

Extent of non-ideal flow in the vessel

Answer

Activation energies of a reaction

Answer

Reaction mechanism

Answer

None of these

Question 2

In case of staged packed bed reactors carrying out exothermic reaction, use

Accepted Answer

All of the above

Answer

High recycle for pure gas

Answer

Plug flow for dilute liquid requiring no large preheating of feed

Answer

Cold shot operations for a dilute solution requiring large preheating to bring the stream upto the reaction temperature

Question 3

The rate expression for a heterogenous catalytic reaction is given by, - rA = K.KA PA(1 + KA.PA + Kr.PR), where K is surface reaction rate constant and KA and KR are absorption equilibrium constants of A and R respectively. If KR PR >> (1 + KA PA), the apparent activation energy EA is equal to (given E is the activation energy for the reaction and ΔHR and ΔHA are the activation energies of adsorption of R and A)

Accepted Answer

E + ΔHA - ΔHR

Answer

E

Answer

E + ΔHA

Answer

ΔHA + ΔHR

Question 4

In Langmuir treatment of adsorption,

Accepted Answer

Whole surface of the catalyst is essentially uniform and the adsorbed molecule has no effect on the rate of adsorption per site

Answer

Whole surface of the catalyst does not have the same activity for adsorption and there is attraction between the adsorbed molecule

Answer

All the adsorption does not take place by the same mechanism

Answer

Extent of adsorption is more than one complete monomolecular layer on the surface

Question 5

If CA is the quantity of reactants initially present, the quantity left after 'n' half periods will be equal to

Accepted Answer

$${\left( {\frac{1}{2}} ight)^{	ext{n}}} \cdot {{	ext{C}}_{	ext{A}}}$$

Answer

$${\left( {\frac{{{{	ext{C}}_{	ext{A}}}}}{2}} ight)^{	ext{n}}}$$

Answer

$${\left( {\frac{{{{	ext{C}}_{	ext{A}}}}}{2}} ight)^{\frac{1}{{	ext{n}}}}}$$

Answer

$${\left( {{{	ext{C}}_{	ext{A}}}} ight)^{\frac{1}{{2{	ext{n}}}}}}$$

Question 6

Pick out the correct statement.

Accepted Answer

A catalyst does not change AH of the reaction

Answer

A catalyst changes the equilibrium point

Answer

Law of mass action was suggested by Le-Chatelier

Answer

The difference between the energy of reactants and that of the products is the activation energy

Question 7

Cold shot cooling is only practical when the feed temperature is __________ than the reaction temperature.

Accepted Answer

Much lower

Answer

Higher

Answer

Much higher

Answer

Lower

Question 8

With an increase in pressure in gaseous phase chemical reactions, the fractional conversion __________ when the number of moles decreases.

Accepted Answer

Increases

Answer

Decreases

Answer

Remains unaffected

Answer

Unpredictable from the data

Question 9

The rate of forward reaction, at chemical equilibrium is____the rate of backward reaction.

Accepted Answer

Equal to

Answer

More than

Answer

Less than

Answer

Either B or C