Select the correct reaction(s) of chlorine.

$\mathrm{Cl}{}_2$ oxidises $\mathrm{H}{}_2\mathrm{S}$ to sulphur, adds across the double bond of ethene, and oxidises $\mathrm{Fe}{}^{2+}$ to $\mathrm{Fe}{}^{3+}$. With cold dilute NaOH the oxidised product is hypochlorite, and chlorate forms only with hot concentrated alkali. Options 1, 2 and 4 are correct.