Write the balanced chemical equation for the reaction of aluminium when heated in air. Also,write the name of the product.

Write the balanced chemical equations for the following reactions:
$(i)$ Hydrogen $+$ Chlorine $\to$ Hydrogen chloride
$(ii)$ Barium chloride $+$ Aluminium sulphate $\to$ Barium sulphate $+$ Aluminium chloride
$(iii)$ Sodium $+$ Water $\to$ Sodium hydroxide $+$ Hydrogen

Define a chemical equation. What is an unbalanced chemical equation called?

Write word equations and then balanced chemical equations for the reactions taking place when:
$(a)$ Dilute sulphuric acid reacts with zinc granules.
$(b)$ Dilute hydrochloric acid reacts with magnesium ribbon.

Write a balanced chemical equation for the reaction in which phosphorus burns in chlorine to form phosphorus pentachloride.

Which compound is formed when dinitrogen gas reacts with dihydrogen gas?