A mixture of $\mathrm{Zn}(\mathrm{OH}){}_2$, $\mathrm{Ni}(\mathrm{OH}){}_2$ and $\mathrm{Mn}(\mathrm{OH}){}_2$ is shaken with excess $\mathrm{NaOH}$ and filtered. Select the correct statements.

1. AThe residue is entirely white because $\mathrm{Ni}(\mathrm{OH}){}_2$ is white
2. BThe residue contains green $\mathrm{Ni}(\mathrm{OH}){}_2$ and white $\mathrm{Mn}(\mathrm{OH}){}_2$ that browns on standing in air
3. CPassing $\mathrm{H}{}_2\mathrm{S}$ through the filtrate gives white $\mathrm{ZnS}$
4. DThe filtrate contains $[\mathrm{Zn}(\mathrm{OH}){}_4]{}^{2-}$