The standard reduction potential for I2/I - is + 0.54V, and the standard reduction potential for Br2/Br - is + 1.07V. Which reaction occurs when bromine is added to an aqueous solution of iodide ions?

1. 2I - + 2Br - → I2 + Br2

2. I2 + 2Br - → Br2 + 2I -

3. I2 + Br2→ 2I - + 2Br -

4. 2I - + Br2→ I2 + 2Br -

Question

Chemistry

Karsyn Henderson

29 May, 21:06

The standard reduction potential for I2/I - is + 0.54V, and the standard reduction potential for Br2/Br - is + 1.07V. Which reaction occurs when bromine is added to an aqueous solution of iodide ions?

1. 2I - + 2Br - → I2 + Br2

2. I2 + 2Br - → Br2 + 2I -

3. I2 + Br2→ 2I - + 2Br -

4. 2I - + Br2→ I2 + 2Br -

+3

Answers (1)

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Karla · Answer 1

The reduction potential for Bromine is stronger than the one for Iodine, as seen by its larger charge. This means that Bromine can oxidize something else (by reducing itself) better than Iodine can, so Bromine gets reduced in the equation. This eliminates 1 and 2, because in these, Bromine is being oxidized (going from - 1 to 0), rather than being reduced.

Number 3 doesn’t work because both Iodine and Bromine are being reduced in the equation, and that’s not how things work in the wonderful world of chemistry - one must be reduced and the other must be oxidized.

Therefore, 4 is the correct answer, as seen by the reduction of Bromine and the oxidation of Iodine.