A magnesium ribbon is burnt in oxygen to give a white compound X accompanied by emission of light. If the burning ribbon is now placed in an atmosphere of nitrogen, it continues to burn and forms a compound Y.

(a) Write the chemical formulae of X and Y.

(b) Write a balanced chemical equation, when X is dissolved in water.

Why do we store silver chloride in dark coloured bottles?

Balance the following chemical equations and identify the type of chemical reaction.

(a) Mg(s) + Cl₂(g) → MgCl₂(s)

(b) HgO(s) ⎯⎯⎯⎯ (Heat) → Hg(l) + O₂(g)

(c) Na(s) + S(s) ⎯⎯⎯⎯ (Fuse) → Na₂S(s)

(d) TiCl₄ (l) + Mg(s) ⎯→ Ti(s) + MgCl₂ (s)

(e) CaO(s) + SiO₂(s) ⎯→ CaSiO₃(s)

(f) H₂O₂ (l) ⎯⎯⎯⎯ UV → H₂O(l) + O₂ (g)

Zinc liberates hydrogen gas when reacted with dilute hydrochloric acid, whereas copper does not. Explain why?

A silver article generally turns black when kept in the open for a few days. The article when rubbed with toothpaste again starts shining.

(a) Why do silver articles turn black when kept in the open for a few days? Name the phenomenon involved.

(b) Name the black substance formed and give its chemical formula.