Question

Which of the following ores is concentrated by the chemical leaching method?
(A) Cinnabar
(B) Argentite
(C) Copper pyrites
(D) Galena

Answer 1

Hint: The process in which ore is treated with chemicals to convert the valuable metals within into soluble salts while the impurity remains insoluble is known as the chemical leaching method. These impurities are then washed out to obtain the pure metal. This method is used when a substance can dissolve in a liquid.

Complete Step by Step Answer:
All four of the ores given in the options are silver ores, but only one of them can be concentrated by the chemical leaching method.
In the process of chemical leaching, the ore is treated with a dilute solution of $KCN$or $NaCN$in the presence of oxygen (air). A metal can be extracted from ore by this method but it is an impure form. The impurities are then removed by filtration.
Argentite is the ore that can be extracted by the chemical leaching method.
The reactions involved in the chemical leaching process of argentite are given as:
Correct option: (B) Argentite.

Additional Information: An example of a leaching process is the leaching of bauxite ($A{{l}_{2}}{{O}_{3}}.2{{H}_{2}}O$ ) with concentrated sodium hydroxide ($NaOH$). This $NaOH$ dissolves the aluminium but the impurities like $Si{{O}_{2}}$,$Ti{{O}_{2}}$, and $F{{e}_{2}}{{O}_{3}}$does not gets dissolved. The leaching process can also be used to extract silver and gold in the presence of an aqueous solution of $KCN$ or $NaCN$. The process of leaching is easier to use and does not lead to any gaseous pollutants.

Note: Another ores like cinnabar, copper pyrites, galena ($PbS$), copper pyrites ($CuFe{{S}_{2}}$) and cinnabar ($HgS$) are also silver ores, but these ores cannot be concentrated by the chemical leaching method.