What occurs when potassium reacts with water?

When potassium reacts with water, it undergoes a vigorous chemical reaction. Potassium is an alkali metal, and when it comes into contact with water, it reacts exothermically, producing potassium hydroxide and hydrogen gas. The heat generated from this reaction is significant enough that it can cause the potassium to melt and often ignite the hydrogen gas, resulting in flames or sparks. The potassium, being less dense than water, will float on the surface while exhibiting this behavior.

This process is characteristic of alkali metals, which become increasingly reactive as you move down the group in the periodic table. The intense reaction is not only due to the production of hydroxide but also due to the rapid release of gas and heat, which contributes to the melting. Thus, the correct answer highlights the key behaviors of potassium during its reaction with water: its ability to melt, float, and potentially ignite, making it an energetic example of alkali metal reactions.