Question

iodine gas (i₂) and solid potassium (k) are produced by the decomposition of solid potassium iodide (ki).
write a balanced chemical equation for this reaction.

Explanation:

Step1: Write the unbalanced equation

The reaction is decomposition of \( \text{KI} \) to \( \text{I}_2 \) and \( \text{K} \). The unbalanced equation is \( \text{KI}(s)
ightarrow\text{K}(s)+\text{I}_2(g) \).

Step2: Balance the iodine atoms

There are 2 iodine atoms on the right - hand side (\( \text{I}_2 \)) and 1 on the left - hand side (\( \text{KI} \)). So, we put a coefficient of 2 in front of \( \text{KI} \): \( 2\text{KI}(s)
ightarrow\text{K}(s)+\text{I}_2(g) \).

Step3: Balance the potassium atoms

After putting a coefficient of 2 in front of \( \text{KI} \), there are 2 potassium atoms on the left - hand side. So, we put a coefficient of 2 in front of \( \text{K} \) on the right - hand side.

Answer:

\( 2\text{KI}(s)
ightarrow2\text{K}(s)+\text{I}_2(g) \)