Upon combustion, any hydrocarbon produces $\mathrm{CO}_2$ and $\mathrm{H}_2\mathrm{O}$. For the given hydrocarbons the reactions may be represented as : (i) Butane : $\mathrm{C}_4\mathrm{H}_{10}+\frac{13}{2}\mathrm{O}_2\xrightarrow{\Delta}4\mathrm{CO}_2+5\mathrm{H}_2\mathrm{O}$ (ii) Pentane : $\mathrm{C}_5\mathrm{H}_{10}+\frac{15}{2}\mathrm{O}_2\xrightarrow{\Delta}5\mathrm{CO}_2+5\mathrm{H}_2\mathrm{O}$ (iii) Hexyne : $\mathrm{C}_6\mathrm{H}_{10}+\frac{17}{2}\mathrm{O}_2\xrightarrow{\Delta}6\mathrm{CO}_2+5\mathrm{H}_2\mathrm{O}$ (iv) Toluene : $\mathrm{C}_7\mathrm{H}_8+9\mathrm{O}_2\xrightarrow{\Delta}7\mathrm{CO}_2+4\mathrm{H}_2\mathrm{O}$