A catalyst increases the rate of a reaction by: MCQ with Answer and Explanation

A catalyst increases the rate of a reaction by:
A. Increasing the temperature
B. Changing the equilibrium constant
C. Increasing the activation energy
D. Providing an alternative path with lower activation energy
Answer: Option D
Solution (By JKSSB Mock Tests)
A catalyst lowers the activation energy barrier by providing a different reaction mechanism. This allows more reactant molecules to have sufficient energy to react. It does not change the thermodynamics (ΔH, equilibrium constant) or get consumed in the reaction. Enzymes are biological catalysts.

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Practice More chemistry Questions

Question #1
Which of the following is an extensive property of matter?
A. Refractive index
B. Boiling point
C. Density
D. Number of moles

Correct Answer: Option D


Explanation:
Extensive properties depend on the amount of substance. Number of moles (or mass, volume) is extensive. Density, refractive index, boiling point are intensive properties – they do not depend on the quantity. For example, 1 liter of water boils at 100°C, same as 10 liters. Intensive properties are useful for identifying substances.

This question belongs to: Science chemistry
Question #2
The alcohol used in antifreeze is:
A. Ethanol
B. Glycerol
C. Ethylene glycol
D. Methanol

Correct Answer: Option C


Explanation:
Ethylene glycol (1,2-ethanediol) is the main component of antifreeze, lowering the freezing point of water. Methanol is toxic, ethanol can be used but evaporates, glycerol is viscous. Ethylene glycol is poisonous if ingested. Propylene glycol is a safer alternative.

This question belongs to: Science chemistry
Question #3
The technique of chromatography is used for:
A. Separating immiscible liquids
B. Separating solids from liquids
C. Separating dissolved substances by differential adsorption
D. Boiling point separation

Correct Answer: Option C


Explanation:
Chromatography separates components of a mixture based on their different affinities for stationary and mobile phases. Used for dyes, drugs, amino acids.

This question belongs to: Science chemistry