Question

Which of the following cations do not react with dilute $HCl$ or Dilute $H_{2}S$?

• A. $F{e}^{2+}$
• B. $F{e}^{3+}$
• C. $C{o}^{2+}$
• D. All of the above

Answer 1

The correct option is D All of the above

$F{e}^{2+},F{e}^{3+},C{o}^{2+}$ belongs to group 3 cations. Cations of this group do not react either with dilute hydrochloric acid, or with hydrogen sulphide in dilute mineral acid medium. However they form precipitates with ammonium sulphide in neutral or ammoniacal medium. Cations of this group are iron (II), iron (III), cobalt(II), nickel(II), manganese(II), chromium(III), aluminium(III), and zinc(II).