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

Which of the statements about the reaction below are incorrect?
$2 PbO_{(s)} + C_{(s)} \longrightarrow 2 Pb_{(s)} + CO_{2(g)}$
$(a)$ Lead is getting reduced.
$(b)$ Carbon dioxide is getting oxidised.
$(c)$ Carbon is getting oxidised.
$(d)$ Lead oxide is getting reduced.

In the refining of silver,the recovery of silver from silver nitrate solution involves displacement by copper metal. Write down the reaction involved.

What does one mean by exothermic and endothermic reactions? Give examples.

Why is respiration considered an exothermic reaction? Explain.

Write the balanced chemical equation for the following and identify the type of reaction in each case.
$(a)$ Potassium bromide $(aq) +$ Barium iodide $(aq) \rightarrow$ Potassium iodide $(aq) +$ Barium bromide $(s)$
$(b)$ Zinc carbonate $(s) \rightarrow$ Zinc oxide $(s) +$ Carbon dioxide $(g)$
$(c)$ Hydrogen $(g) +$ Chlorine $(g) \rightarrow$ Hydrogen chloride $(g)$
$(d)$ Magnesium $(s) +$ Hydrochloric acid $(aq) \rightarrow$ Magnesium chloride $(aq) +$ Hydrogen $(g)$