Question

On passing $H_{2}S$ gas to the original solution from group III cation analysis gives a black precipitate. This indicate the presence of

• A. $N{i}^{2+}$
• B. $Z{n}^{2+}$
• C. $M{n}^{2+}$
• D. All of the above

Answer 1

The correct option is A $N{i}^{2+}$

While passing $H_{2}S$ gas in the solution of group III, appearence of white, black or flesh coloured indicates the presence of group IV cations.
Fourth group cations are precipitated​ as their sulphides.
Black colour precipitate indicate the presence of $N{i}^{2+}$
White colour precipitate indicate the presence of $Z{n}^{2+}$
Flesh colour precipitate indicate the presence of $M{n}^{2+}$

Hence, option (b) is correct.