Two amperes of current is passed through acidulated water for ‘t’ seconds to decompose 18 grams of water .  Value of ‘t’ is equal to

$$\begin{gathered} \mathrm{At} \mathrm{anode} \\ 2{\mathrm{H}}_2\mathrm{O}\to 4{\mathrm{H}}^{+}+4{\mathrm{e}}^{-}+{\mathrm{O}}_2 \end{gathered}$$

$$\begin{gathered} \mathrm{At} \mathrm{cathode} \\ [2{\mathrm{H}}_2\mathrm{O}+2{\mathrm{e}}^{-}\to {\mathrm{H}}_2+2{\mathrm{OH}}^{-}]\times 2 \end{gathered}$$

$$\begin{gathered} \mathrm{Net} \mathrm{reaction} \\ 2{\mathrm{H}}_2\mathrm{O}\stackrel{4\mathrm{F}}{\to }2{\mathrm{H}}_2+{\mathrm{O}}_2 \end{gathered}$$

$$\begin{gathered} 36\mathrm{g} {\mathrm{H}}_2\mathrm{O} \mathrm{require} 4\mathrm{F} \\ 18\mathrm{g} {\mathrm{H}}_2\mathrm{O} \mathrm{require} 2\mathrm{F} \\ \mathrm{Q}=\mathrm{it} \\ 2\times 96500=2\times \mathrm{t} \\ \mathrm{t}=96500 \mathrm{seconds} \end{gathered}$$