DP Chemistry (first assessment 2025)

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Question 22M.1A.SL.TZ1.23

Date	May 2022	Marks available	[Maximum mark: 1]	Reference code	22M.1A.SL.TZ1.23
Level	SL	Paper	1A	Time zone	TZ1
Command term	Determine	Question number	23	Adapted from	N/A

23.

[Maximum mark: 1]

22M.1A.SL.TZ1.23

How many electrons are needed when the following half-equation is balanced using the lowest possible whole numbers?

__ NO₃^– (aq) + __ H⁺(aq) + __ e^– → __ NO (g) + __ H₂O (l)

A. 1

B. 2

C. 3

D. 5

[1]

Markscheme

C

Syllabus sections

Reactivity 3. What are the mechanisms of chemical change? » Reactivity 3.2—Electron transfer reactions » Reactivity 3.2.2—Half-equations separate the processes of oxidation and reduction, showing the loss or gain of electrons. Deduce redox half-equations and equations in acidic or neutral solutions.