Question

The ash obtained from burning of magnesium ribbon is dissolved in water. The solution is tested by litmus paper for acidic nature. Which of the following options is/ are correct?

• A. red litmus turns blue
• B. blue litmus turns red
• C. blue litmus remains blue
• D. litmus test cannot test acidic or basic nature

Answer 1

Answer: (A), (C)

blue litmus remains blue

Ash from magnesium ribbon is magnesium oxide. When this oxide is dissolved in water, it liberates hydroxyl [$O{H}^{-}$] ions in water. This makes the solution basic. Hence, we know in the basic solution turns red litmus into blue.