CAIE A-Level Chemistry A2 24.2.6 From E Questions

Practise using standard electrode potentials to identify oxidising or reducing agents and predict whether reactions occur.

Exam points

compare the two standard reduction potentials to decide which species can oxidise or reduce the other under standard conditions

[Maximum number: 2]

Some electrode potentials are shown in Table 3.1.

Table 3.1

(a)

The vanadium-containing species in the electrode reactions given in Table 3.1 are $\mathrm{V}, \mathrm{V}^{2+}$ , $\mathrm{V}^{3+}, \mathrm{VO}^{2+}$ and $\mathrm{VO}_{2}{ }^{+}$ .

[ 2 ]

(i)

Identify one vanadium-containing species that does not react with $\mathrm{Fe}^{2+}$ ions under standard conditions.

Use data from Table 3.1 to explain your answer.

[ 1 ]

(for specified $\mathrm{V}^{2+}, \mathrm{V}^{3+}$ or $\mathrm{VO}^{2+}$ ) $\mathrm{E}^{\ominus}$ is more positive than / above -0.44 AND more negative than / below 0.77 V [1]

(ii)

Identify all the vanadium-containing species that will react with $\mathrm{Fe}^{2+}$ ions under standard conditions.

[ 1 ]

V and $\mathrm{VO}_{2}{ }^{+}$ [1]

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CAIE A-Level Chemistry A2 24.2.6 From E Questions question 1

Question (a)

Question (i)

Question (ii)