Question

Write balanced chemical equations for the following reactions.
(a) the action of water on calcium oxide
(b) the action of dilute nitric acid on zinc
(c) the reaction between sulphur dioxide and water
(d) the reaction between sodium and water
(e) the reaction between calcium and sulphuric acid
(f) the reaction between iron and copper sulphate solution
(g) the reaction between potassium and water

Answer 1

(a) Calcium oxide reacts with water to form calcium hydroxide along with liberation of excess heat. The balanced chemical equation is:

$$\begin{gathered} \mathrm{CaO}+{\mathrm{H}}_2\mathrm{O}\stackrel{}{\to }\mathrm{Ca}{\left(\mathrm{OH}\right)}_2+\mathrm{Excess}\mathrm{heat} \\ \mathrm{Calcium}\mathrm{Oxide}\mathrm{Water}\mathrm{Calcium}\mathrm{hydroxide} \end{gathered}$$

(b) Zinc reacts with dil. nitric acid to form zinc nitrate along with the evolution of nitrous oxide. The balanced chemical equation is:​

$$\begin{gathered} 4\mathrm{Zn}+\mathrm{dil}.10{\mathrm{HNO}}_3\stackrel{}{\to }4\mathrm{Zn}{\left({\mathrm{NO}}_3\right)}_2+{\mathrm{N}}_2\mathrm{O}+5{\mathrm{H}}_2\mathrm{O} \\ \mathrm{Zinc}\mathrm{dil}.\mathrm{Nitric}\mathrm{acid}\mathrm{Zinc}\mathrm{nitrate}\mathrm{Nitrous}\mathrm{oxide}\mathrm{Water} \end{gathered}$$

(c) Sulphur dioxide reacts with water forming sulphurous acid. The balanced chemical equation is:​

$$\begin{gathered} {\mathrm{SO}}_2+{\mathrm{H}}_2\mathrm{O}\stackrel{}{\to }{\mathrm{H}}_2{\mathrm{SO}}_3 \\ \mathrm{Sulphur}\mathrm{dioxide}\mathrm{Water}\mathrm{Sulphorous}\mathrm{acid} \end{gathered}$$

(d) Sodium reacts with water violently forming sodium hydroxide and hydrogen gas with an excess of heat generation. The balanced chemical equation is:​

$$\begin{gathered} 2\mathrm{Na}+2{\mathrm{H}}_2\mathrm{O}\stackrel{}{\to }2\mathrm{NaOH}+{\mathrm{H}}_2(\mathrm{Excess}\mathrm{of}\mathrm{heat}) \\ \mathrm{Sodium}\mathrm{Water}\mathrm{Sodium}\mathrm{hydroxide}\mathrm{Hydrogen}\mathrm{gas} \end{gathered}$$

(e) Calcium reacts with sulphuric acid forming calcium sulphate and hydrogen gas. The balanced chemical equation is:​​

$$\begin{gathered} \mathrm{Ca}+{\mathrm{H}}_2{\mathrm{SO}}_4\stackrel{}{\to }{\mathrm{CaSO}}_4+{\mathrm{H}}_2 \\ \mathrm{Calcium}\mathrm{Sulphuric}\mathrm{acid}\mathrm{Calcium}\mathrm{sulphate}\mathrm{Hydrogen}\mathrm{gas} \end{gathered}$$

(f) Iron being more reactive than copper displaces copper from copper sulphate solution forming iron sulphate. The balanced chemical equation is:​​

$$\begin{gathered} \mathrm{Fe}+{\mathrm{CuSO}}_4\stackrel{}{\to }{\mathrm{FeSO}}_4+\mathrm{Cu} \\ \mathrm{Iron}\mathrm{Copper}\mathrm{sulphate}\mathrm{Iron}\mathrm{sulphate}\mathrm{Copper} \end{gathered}$$

(g) Potassium reacts with water violently forming potassium hydroxide and hydrogen gas with excess of heat generation. The balanced chemical equation is:​​

$$\begin{gathered} 2\mathrm{K}+2{\mathrm{H}}_2\mathrm{O}\stackrel{}{\to }2\mathrm{KOH}+{\mathrm{H}}_2(\mathrm{Excess}\mathrm{of}\mathrm{heat}) \\ \mathrm{Potassium}\mathrm{Water}\mathrm{Potassium}\mathrm{hydroxide}\mathrm{Hydrogen}\mathrm{gas} \end{gathered}$$