Hydrogen peroxide is used as an antiseptic because it: MCQ with Answer and Explanation

Hydrogen peroxide is used as an antiseptic because it:
A. Is a strong acid
B. Reduces bacteria
C. Dehydrates cells
D. Oxidizes bacterial cell components
Answer: Option D
Solution (By JKExamLibrary)
H₂O₂ is a strong oxidizing agent that damages bacterial cell walls, membranes, and essential biomolecules through oxidation, killing microorganisms. It is used as a 3% solution for wound cleaning. The foaming action is due to catalase in tissues breaking it down, releasing O₂. It is not a reducing agent, acid, or dehydrating agent.

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Practice More chemistry Questions

Question #1
Which of the following reactions is an oxidation-reduction reaction?
A. NaOH + HCl → NaCl + H₂O
B. CaCO₃ → CaO + CO₂
C. NaCl + AgNO₃ → AgCl + NaNO₃
D. H₂ + Cl₂ → 2HCl

Correct Answer: Option D


Explanation:
In H₂ + Cl₂ → 2HCl, hydrogen is oxidized (0 to +1) and chlorine is reduced (0 to -1). Thus it's a redox reaction. The others: A and C are double displacement with no oxidation state change; D is decomposition with no change (Ca +2, C +4, O -2 throughout).

This question belongs to: Science chemistry
Question #2
The chief ore of iron is:
A. Galena
B. Bauxite
C. Cinnabar
D. Haematite

Correct Answer: Option D


Explanation:
Haematite (Fe₂O₃) is a major ore of iron. Bauxite is aluminium ore, galena is lead sulfide, cinnabar is mercury sulfide. Magnetite (Fe₃O₄) is another iron ore.

This question belongs to: Science chemistry
Question #3
Which of the following is a decomposition reaction used in black and white photography?
A. 2AgCl → 2Ag + Cl₂
B. 2H₂O → 2H₂ + O₂
C. 2AgBr → 2Ag + Br₂
D. CaCO₃ → CaO + CO₂

Correct Answer: Option C


Explanation:
Silver bromide (AgBr) decomposes on exposure to light (photochemical decomposition) forming silver and bromine: 2AgBr(s) → 2Ag(s) + Br₂(g). This is used in photographic films to capture images. AgCl also light-sensitive but AgBr is primarily used. Calcium carbonate decomposition is thermal. Water electrolysis is electric decomposition.

This question belongs to: Science chemistry