Multiple choice

The elements whose oxides can turn litmus solution blue are

  1. carbon and sulphur

  2. sodium and carbon

  3. potassium and magnesium

  4. magnesium and sulphur

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Oxides of potassium and magnesium turn litmus solution blue because potassium and magnesium are metals. Metals form basic oxides which turn litmus solution blue.