Write the IUPAC names for the following compounds.

$\text{Step 1: (i)(a) Iron reacts with copper sulphate (displacement reaction).}$

$\mathrm{Fe + CuSO_4 \to FeSO_4 + Cu}$

$\text{Step 2: (i)(b) Manganese dioxide reacts with hydrochloric acid.}$

$\mathrm{MnO_2 + 4HCl \to MnCl_2 + Cl_2 + 2H_2O}$

$\text{Step 3: (ii) Thermal decomposition of lead nitrate.}$

$2Pb(NO_3)_2 \xrightarrow{\Delta} 2PbO + 4NO_2 + \mathrm{O_2}$

$\text{Step 4: (iii)(a) The given structure is } \chemfig{H_3C-CHO}$

Ethanal

$\text{Step 5: (iii)(b) The given structure is } \chemfig{HC\equiv C-CH_3}$

Prop-1-yne

$\boxed{Final answers bolded above.}$