DP Chemistry (first assessment 2025)

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Question 21M.1A.SL.TZ2.21

Date	May 2021	Marks available	[Maximum mark: 1]	Reference code	21M.1A.SL.TZ2.21
Level	SL	Paper	1A	Time zone	TZ2
Command term	Deduce	Question number	21	Adapted from	N/A

21.

[Maximum mark: 1]

21M.1A.SL.TZ2.21

What is the oxidation state of oxygen in H₂O₂?

A. −2

B. −1

C. +1

D. +2

[1]

Markscheme

B

Syllabus sections

Structure 3. Classification of matter » Structure 3.1—The periodic table: Classification of elements » Structure 3.1.6—The oxidation state is a number assigned to an atom to show the number of electrons transferred in forming a bond. It is the charge that atom would have if the compound were composed of ions. Deduce the oxidation states of an atom in an ion or a compound.