Question

When metal X is treated with a dilute acid Y, then a gas Z is evolved which burns readily by making a little explosion.

1. Name any two metals which can behave like metal X.
2. Name any two acids which can behave like acid Y.
3. Name the gas Z.
4. Is the gas Z lighter than or heavier than air?
5. Is the reaction between metal X and dilute acid Y exothermic or endothermic?
6. By taking a specific example of metal X and dilute acid Y, write a balanced chemical equation for the reaction which takes place. Also indicate physical states of all the reactants and products.

Answer 1

1. Zinc (Zn) and magnesium (Mg) metals can behave like metal X.
2. Sulphuric acid (H₂SO₄) and hydrochloric acid (HCl) can behave like acid Y.
3. Gas Z is hydrogen gas (H₂).
4. Gas Z (i.e., hydrogen) is lighter than air because it is the lightest element in the periodic table.
5. The reaction between metal X and dilute acid Y is exothermic because it produces a huge amount of heat.
6. If X is zinc and Y is sulphuric acid, then the equation can be written as follows:
   \[\ce{Zn_{(s)} + H2SO4_{(aq)} -> ZnSO4_{(aq)} + H2_{(g)}}\]