Balance the following chemical equations and identify the type of chemical reaction.
$(a)$ $TiCl_4(l) + Mg(s) \to Ti(s) + MgCl_2(s)$
$(b)$ $CaO(s) + SiO_2(s) \to CaSiO_3(s)$
$(c)$ $H_2O_2(l) \xrightarrow{UV} H_2O(l) + O_2(g)$

Balance the following chemical equations:
$(a)$ $KClO_{3} \longrightarrow KCl + O_{2}$
$(b)$ $Na_{2}CO_{3} + HCl \longrightarrow NaCl + H_{2}O + CO_{2}$

$(a)$ Why is the corrosion of iron a serious problem?
$(b)$ How can we prevent corrosion?

You could have noted that when copper powder is heated in a china dish, the surface of copper powder becomes coated with black coloured substance.
$(i)$ Why has this black coloured substance formed?
$(ii)$ What is this black substance?
$(iii)$ Write the chemical equation of the reaction that takes place.

Translate the following statement into a chemical equation and balance it:
$(a)$ Aluminium chloride reacts with ammonium hydroxide to form a gelatinous white precipitate of aluminium hydroxide and a salt of ammonium chloride.

Three beakers labelled as $A$,$B$ and $C$ each containing $25 \, mL$ of water were taken. $A$ small amount of $NaOH$,anhydrous $CuSO_4$ and $NaCl$ were added to the beakers $A$,$B$ and $C$ respectively. It was observed that there was an increase in the temperature of the solutions contained in beakers $A$ and $B$,whereas in case of beaker $C$,the temperature of the solution falls. Which one of the following statement$(s)$ is(are) correct?
$(i)$ In beakers $A$ and $B$,exothermic process has occurred.
$(ii)$ In beakers $A$ and $B$,endothermic process has occurred.
$(iii)$ In beaker $C$ exothermic process has occurred.
$(iv)$ In beaker $C$ endothermic process has occurred.