A catalyst that slows down a reaction is called: MCQ with Answer and Explanation

A catalyst that slows down a reaction is called:
A. Autocatalyst
B. Biocatalyst
C. Positive catalyst
D. Negative catalyst (inhibitor)
Answer: Option D
Solution (By JKExamLibrary)
A negative catalyst (inhibitor) decreases the rate of a reaction by increasing activation energy or destroying active intermediates. Example: phosphoric acid inhibits H₂O₂ decomposition. Positive catalysts speed up, enzymes are biocatalysts, autocatalysts are products that catalyze their own formation.

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Practice More chemistry Questions

Question #1
Identify the correct statement regarding the physical properties of matter.
A. Solids have the maximum intermolecular space.
B. Gases cannot be compressed.
C. Liquids have a definite volume but no definite shape.
D. Gases have the highest density among the three states.

Correct Answer: Option C


Explanation:
Liquids have a definite volume but take the shape of their container. Solids have the least intermolecular space and highest density. Gases have maximum intermolecular space and are highly compressible. This relates directly to the kinetic theory of matter, which describes particle arrangement and movement in different states.

This question belongs to: Science chemistry
Question #2
Chlorine is used in water treatment primarily to:
A. Add minerals
B. Kill pathogenic microorganisms
C. Remove suspended particles
D. Improve taste

Correct Answer: Option B


Explanation:
Chlorine acts as a disinfectant, killing bacteria, viruses, and other pathogens, making water safe for drinking. It forms hypochlorous acid (HOCl) in water which is a strong oxidizing agent. Sedimentation and filtration remove suspended particles. Taste may be affected if excess chlorine or by-products form. Chlorine residual protects water in distribution pipes.

This question belongs to: Science chemistry
Question #3
The separation of two liquids with a boiling point difference of less than 25 K is best achieved by:
A. Vacuum distillation
B. Simple distillation
C. Steam distillation
D. Fractional distillation

Correct Answer: Option D


Explanation:
Fractional distillation is specifically designed to separate miscible liquids whose boiling points differ by less than 25 K. It uses a fractionating column which provides surfaces for repeated evaporation and condensation, enriching the vapor with the more volatile component before it reaches the condenser.

This question belongs to: Science chemistry