Questions and answers for exam Preparation

MCQs

Total Questions : 2307 | Page 230 of 231 pages

Question 2291. Pick out the wrong statement?

Catalytic activity of enzyme catalysed reactions which is affected by temperature, pH value & chemical agents, is maximum at a temperature of about 45
Most of the enzyme catalysed reactions involve at least two substrates
Enzymes help in increasing the activation energy of the reaction
Equilibrium concentrations in enzyme catalysed reactions can be calculated by using the thermodynamic properties of substrates & products

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Answer: Option C. -> Enzymes help in increasing the activation energy of the reaction
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 2292. Pick out the wrong statement?

Exit age description function E. and internal age distribution function (I) are related as, E = -(dI/dθ)
Chemisorption studies are useful in the determination of catalyst surface area and pore size distribution
A higher temperature favours the reaction of higher activation energy
A catalyst increases the potential energy barrier over which the reactants must pass to form products

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Answer: Option D. -> A catalyst increases the potential energy barrier over which the reactants must pass to form products
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 2293. Pick out the wrong statement?

A particular chemical reaction is more temperature sensitive at low temperatures
A very high value of equilibrium constant, K (K >> 1) indicates that the reaction is practically irreversible in nature
The intercept of the Arrhenius plot is called the ‘activation energy’
Non-ideal flow takes place in reactors due to recycling, channeling or by creation of stagnant regions

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Answer: Option C. -> The intercept of the Arrhenius plot is called the ‘activation energy’
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 2294. Pick out the wrong statement ?

The vessel dispersion number (D/UL) for plug flow and mixed flow approaches zero and infinity respectively
Space time in a flow reactor is a measure of its capacity and is equal to the residence time when the density of reaction mixture is constant
Mixed reactor is always smaller than the plug flow reactor for all positive reaction orders for a particular duty
In an ideal tubular flow reactor, mixing takes place in radial direction and there is no mixing in longitudinal direction

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Answer: Option C. -> Mixed reactor is always smaller than the plug flow reactor for all positive reaction orders for a particular duty
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 2295. Pick out the correct statement?

In catalytic reactions, the catalyst reacts with the reactants
A catalyst initiates a chemical reaction
A catalyst lowers the activation energy of the reacting molecules
A catalyst cannot be recovered chemically unchanged at the end of the chemical reaction

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Answer: Option A. -> In catalytic reactions, the catalyst reacts with the reactants
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 2296. Pick out the wrong statement?

Use of different catalysts in a reversible catalytic chemical reaction does not change the equilibrium composition
Alumina is added as a promoter to iron catalyst in ammonia synthesis reaction
Activation energy for a reaction is obtained from the intercept of the Arrhenius plot
Presence of inerts affects the equilibrium conversion of

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Answer: Option C. -> Activation energy for a reaction is obtained from the intercept of the Arrhenius plot
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 2297. Pick out the wrong statement pertaining to space velocity of flow reactors?

The unit of space velocity is (time)-1
The space velocity of 3 hr-1 means that three reactor volumes of feed at specified conditions are being fed into the reactor every hour
The space velocity of 3 hr-1 means that one third reactor volume of feed at specified conditions are being fed into the reactor
None of these

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Answer: Option C. -> The space velocity of 3 hr-1 means that one third reactor volume of feed at specified conditions are being fed into the reactor
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 2298. Pick out the wrong statement ?

‘Hold back’ is defined as the fraction of material that stays longer than the mean residence time
Study of non-ideal flow reactor is done experimentally by stimulus-response technique
For studying a chemical reaction, it is desirable to monitor the reactants during initial stages and the products during the final stages of reaction
A batch reactor cannot be used to study the kinetics of catalytic reaction

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Answer: Option D. -> A batch reactor cannot be used to study the kinetics of catalytic reaction
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 2299. Pick out the wrong statement ?

A catalyst does not alter the final position of equilibrium in a reversible reaction
A catalyst initiates a reaction
A catalyst is specific in reaction
A catalyst remains unchanged in chemical composition at the end the reaction

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Answer: Option B. -> A catalyst initiates a reaction
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!

Question 2300. Pick out the wrong statement ?

Visible radiation provides the necessary activation energy in photochemical reactions
The order and molecularity of a complex reaction may not be the same
For a second order reaction, the slope of the graph/plot between rate and (concentration) is equal to the rate constant (k)
Molecularity of the reaction is always a whole number greater than zero

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Answer: Option B. -> The order and molecularity of a complex reaction may not be the same
NO EXPLANATION IS AVAILABLE FOR THIS QUESTION!