When $ZnS$ and $PbS$ minerals are present together, then $NaCN$ is added to separate them in the froth floatation process as a depressant, because

Which of the following ore and metal are correctly matched :

Ore $\rightarrow $ Metal

‘Lapis-Lazuli’ is a blue coloured precious stone. It is mineral of the class

Given below are two statements : one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R).$

Assertion $(A) :$ Aluminium is extracted from bauxite by the electrolysis of molten mixture of $\mathrm{Al}_{2} \mathrm{O}_{3}$ with cryolite.

Reason $(R):$ The oxidation state of $Al$ in cryolite is $+3$.

In the light of the above statements, choose the most appropriate answer from the options given below:

Correct for above reaction

$Ag\, + \,\mathop {NaCN}\limits_{(0.5\,\% )} \, + \,{H_2}O\, + \,{O_2} \to $ Soluble complex $\xrightarrow{{Zn}}\mathop B\limits_{complex} \, + \,Ag$