Question

What are the Group 3 cations $?$

Answer 1

Hint : We know that cations are the positively charged ions that have lost one or more electrons, gaining a positive charge. Whereas anions are negatively charged ions that have gained one or more electrons, acquiring a negative charge. The cations are classified into five groups on the basis of their behaviours. Group 3 cations are one of the groups of cations.

Complete Step By Step Answer:
Analysis of metallic elements in compounds is an integral part of chemical research. The mean purpose of this experiment is to learn the techniques to separate and identify some common cations. The systematic analysis of cations is an integral part of the salt analysis (or Qualitative analysis). Qualitative analysis is the systematic approach that involves precipitation reaction to remove cations sequentially from a mixture.
Group $3$ cations are $A{l^{3 + }}$. $F{e^{3 + }}$, $C{o^{2 + }}$, $N{i^{2 + }}$, $C{r^{3 + }}$, $Z{n^{2 + }}$ and $M{n^{2 + }}$which are form insoluble sulfides or hydroxides in alkaline medium and are also separated from the solution. After isolating the insoluble sulfides in acidic medium, the solution is made basic and the metallic sulfides having larger Ksp values such as $ZnS$, $NiS$, $CoS$ and $MnS$ precipitate.

Note :
Note that Group $3$cations is also called the hydroxides group, because it is made up of cations which precipitate as hydroxides in ammonia alkaline solution. The cations are classified as Group $1$ cations, Group $2$ cations, Group $3$ cations, Group $4$ cations and Group $5$ cations.
Group $1$ cations are $A{g^ + }$, $Hg_2^{2 + }$ and $P{b^{2 + }}$, which are metallic cations form insoluble chlorides with hydrochloric acid. Group $2$ cations are $H{g^{2 + }}$, $P{b^{2 + }}$, $C{u^{2 + }}$ , $C{d^{2 + }}$, $B{i^{3 + }}$, $A{s^{3 + }}$, $S{b^{3 + }}$ and $S{b^{3 + }}$ which form insoluble sulphides in acidic medium. Group $4$ cations are $C{a^{2 + }}$, $S{r^{2 + }}$and $B{a^{2 + }}$ which form carbonate precipitates. whereas Group $5$ cations are $M{g^{2 + }}$, $N{a^ + }$, ${K^ + }$ and $N{H_4}^ +$ which remains in the final solution.