Write the general formula of alkene homologous series.

The members of same class of organic compounds when arranged in the order of ascending molecular mass, such that they differ from each other by $-{\mathrm{CH}}_2$ group are called :

One mole of a hydrocarbon '$\mathrm{P}$' on complete combustion produces ${\mathrm{CO}}_2$ and ${\mathrm{H}}_2\mathrm{O}$ in the molar ratio $1:1$. The succeeding homologue of '$\mathrm{S}$' is '$\mathrm{Q}$' while preceding homologue is '$\mathrm{O}$'. The name of the homologous series is '$\mathrm{R}$'. Identify $\mathrm{O}, \mathrm{P}, \mathrm{Q}$ and $\mathrm{R}$.

Read the given passage and fill in the blanks by choosing an appropriate option.

The molar ratio of CO₂ and H₂O produced by the combustion of one mole of hydrocarbon     i     is 5:4. The succeeding homologue of i is    ii     . While preceding homologue is    iii   .