Question

What is the empirical formula of potassium chloride?

Answer 1

The empirical formula for potassium chloride is `"KCl"`.

Explanation:

The empirical formula for a compound is the lowest whole number ratio of elements in one molecule or formula unit of the compound. The chemical formula for an ionic compound such as `"KCl"` is always the same as its empirical formula.

We can determine the empirical formula for potassium chloride by using the charges on the ions. Potassium ions have a `1+` charge, and the formula `"K"^+"`, and chloride ions have a `1-` charge, and the formula `"Cl"^(-)"`. All empirical formulas have a net charge of zero. So the ratios of the positive and negative ions must result in an overall charge of zero. In the case of potassium and chlorine, a `1:1` ratio results in a net charge of zero. So the formula for potassium chloride is `"KCl"`.

`"K"^++"Cl"^(-)` `rarr` `"KCl"`