Chemistry - Salt Analysis Question with Solution | TestHub

Metal (M) is a white, crystalline metal and is not appreciably ductile or malleable. It has a very high melting point. The metal is soluble in dilute or concentrated hydrochloric acid. If air is excluded, Metal(II) ions are formed:

$M+2{\mathrm{H}}^{+}\to M^{+2}+{\mathrm{H}}_2\uparrow$.

$M+2\mathrm{HCl}\to M^{+2}+2{\mathrm{Cl}}^{-}+{\mathrm{H}}_2\uparrow$

Metal(II) ions are rather unstable as they are strong reducing agents; they decompose even in acidic solution with the formation of hydrogen and $M^{+3}$.

In the presence of atmospheric oxygen, metal (M) gets partly or wholly oxidized to the trivalent state:

$4M^{+2}+{\mathrm{O}}_2+4{\mathrm{H}}^{+}\to 4M^{+3}+2{\mathrm{H}}_2\mathrm{O}$.

Dilute sulfuric acid attacks metal (M) slowly, with the formation of hydrogen. In hot, concentrated sulfuric acid, metal (M) dissolves readily to form metal(III) ions and sulfur dioxide: $2M+6{\mathrm{H}}_2{\mathrm{SO}}_4\to 2M^{+3}+3{\mathrm{SO}}_4^{-2}+3{\mathrm{SO}}_2\uparrow +6{\mathrm{H}}_2\mathrm{O}$.

Highly concentrated nitric acid renders metal (M) passive.