How is a chemical equation written? Illustrate with an example.

Reaction writing should be done in a systematic manner, using the conventions followed. These are illustrated with the help of an example. Let it be required to write a chemical equation that describes the reaction between magnesium and sulphuric acid to produce magnesium sulphate and hydrogen.

(i) Write the symbols of all the substances involved in the reaction—first the reactants and then the products—one after the other ON THE SAME LINE

$$\begin{gathered} \mathrm{Rectants} \mathrm{Products} \\ \mathrm{Mg} {\mathrm{H}}_2{\mathrm{SO}}_4 {\mathrm{MgSO}}_4 {\mathrm{H}}_2 \end{gathered}$$

(ii)    Separate the reacting substances from the products by a symbol meaning ‘produce’. The sign→ (an arrow) or sometimes sign (equal) = is used for this purpose

Mg H₂SO₄ → MgSO₄ H₂

(iii)    Then put + sign between the reactants indicating that these ‘react’ and a (plus) + sign between the products which signifies ‘and’,

Mg + H₂SO₄ → MgSO₄ +  H₂

(iv) The reactant are writeen on the left hand side. The product are written on the right hand side.