Question

A silvery-white metal X taken in the form of ribbon, when ignited, burns in air with a dazzling white flame to form a white powder Y. When water is added to powder Y, it dissolves partially to form another substance Z.

1. What could metal X be?
2. What is powder Y?
3. With which substance metal X combines to form powder Y?
4. What is substance Z? Name one domestic use of substance Z.
5. Write a balanced chemical equation of the reaction which takes place when metal X burns in air to form powder Y.

Answer 1

1. Metal X could be magnesium metal.
2. Powder Y is magnesium oxide (MgO).
3. Magnesium metal (X) combines with oxygen gas to form powdery magnesium oxide (Y).
4. Substance Z is magnesium hydroxide [Mg(OH)₂]. It is domestically used as an antacid to relieve acidity, indigestion, or heartburn.
5. \[\ce{2Mg_{(s)} + O2_{(g)} -> 2MgO_{(s)}}\]