Question

Given, $N{a_2}S{O_3},N{a_2}{S_2}{O_3},N{a_2}C{O_3},N{a_2}Cr{O_4}$ are separately treated with $AgN{O_3}$ solution. In how many cases is/are red ppt obtained?

Answer 1

Sodium sulfate, sodium carbonate, and sodium chromate are the chemical compounds consisting of sodium as cation and the other groups as anions. When these compounds were treated with silver nitrate undergo the formation of new compounds which are of different colors.

Complete answer:
Sodium is a metal that can easily undergo loss of electrons. It can exist as a cation and forms a compound with anionic groups like chromate, sulfate, carbonate, and thiosulphate.
Silver nitrate is a chemical compound consisting of molecular formula $AgN{O_3}$ .
When sodium sulphate $\left( {N{a_2}S{O_3}} \right)$ , sodium thiosulphate $\left( {N{a_2}{S_2}{O_3}} \right)$ , sodium carbonate $\left( {N{a_2}C{O_3}} \right)$ , and sodium chromate $\left( {N{a_2}Cr{O_4}} \right)$ were treated with silver nitrate solution.
Silver gets displaced in the place of sodium and forms chemical compounds known as silver sulphate $\left( {A{g_2}S{O_3}} \right)$, silver thiosulphate $\left( {A{g_2}{S_2}{O_3}} \right)$ , silver carbonate $\left( {A{g_2}C{O_3}} \right)$ , and silver chromate $\left( {A{g_2}Cr{O_4}} \right)$ were formed.
The compounds silver sulphate $\left( {A{g_2}S{O_3}} \right)$, silver thiosulphate $\left( {A{g_2}{S_2}{O_3}} \right)$ are white in colour. The compound silver carbonate $\left( {A{g_2}C{O_3}} \right)$ is yellow in colour. The compound silver chromate $\left( {A{g_2}Cr{O_4}} \right)$ is red in colour.
In addition to the silver chromate, the compound sodium nitrate will be formed. The chemical reaction will be as follows:
$N{a_2}Cr{O_4} + 2AgN{O_3} \to A{g_2}Cr{O_4}(red) + 2NaN{O_3}$
Thus, the compound silver chromate is red in color.
When the given compounds were separately treated with the silver nitrate solution, in the case of sodium chromate only red ppt is obtained.

Note:
Silver nitrate when used in the combination of ammonium solution it can be known as Tollens’s reagent. It can be mainly used for the identification of carbonyl compounds. As silver ppt will be obtained. Silver nitrate solution also causes staining on the skin which is a chemical burn.