Question

Leaching can be used for the extraction of which metals?
$\left(i\right)Pb$
$\left(ii\right)Al$
$\left(iii\right)Ag$
$\left(iv\right)Au$

• A. (ii), (iii) and (iv)
• B. (i), (ii) and (iii)
• C. (ii) and (iv)
• D. (iii) and (iv)

Answer 1

The correct option is A (ii), (iii) and (iv)

Leaching is used if the ore is soluble in some suitable solvent i.e. acids, bases and some chemical reagents while the gangue particles are insoluble.
It is used for the extraction of Al ore, Ag ore and Au ore.
Al is treated with $NaOH$ to form soluble complex (sodium aluminate).
Ag and Au are treated with $NaCN$ in the presense of oxygen and water to form soluble cyanides. Thus option (a) is the correct option.

Hence, the correct options is (A).