Salt preparations

1 mark · Normal

Which method is most suitable for preparing a pure, dry sample of potassium nitrate in the laboratory?

Show answer

Correct option: Reacting dilute nitric acid with potassium hydroxide and crystallising from solution

Common mistakes: Choosing filtration when both products are soluble; Selecting precipitation for potassium nitrate

Show mark scheme and worked solution

Marking points

B1 · 1 mark · Correct option selected.

Worked solution

Potassium nitrate is a soluble salt, so the correct method is to react dilute nitric acid with potassium hydroxide, then crystallise potassium nitrate from the solution.