On addition of aqueous $NaOH$ to a salt solution,a white gelatinous precipitate is formed,which dissolves in excess alkali. The salt solution contains

Which of the following statements is incorrect regarding $Fe^{2+}$ and $Fe^{3+}$ cations?

An inorganic compound $X$ on treatment with concentrated $H_{2}SO_{4}$ produces brown fumes and gives a dark brown ring with $FeSO_{4}$ in the presence of concentrated $H_{2}SO_{4}$. Also,compound $X$ gives a precipitate $Y$ when its solution in dilute $HCl$ is treated with $H_{2}S$ gas. The precipitate $Y$ on treatment with concentrated $HNO_{3}$ followed by excess of $NH_{4}OH$ further gives a deep blue coloured solution. Compound $X$ is:

When $H_2S$ gas is passed through an $HCl$ solution containing $CuCl_2, HgCl_2, BiCl_3$,and $CoCl_2$,which of the following will not precipitate?

Upon treatment with ammoniacal $H_2S$,the metal ion that precipitates as a sulfide is

Sodium nitroprusside when reacts with a solution of $Na_2S$,produces: