Among statements (a) $-(d)$, the correct ones are :
(a) Lime stone is decomposed to $\mathrm{CaO}$ during the extraction of iron from its oxides.
(b) In the extraction of silver, silver is extracted as an anionic complex.
(c) Nickel is purified by Mond's process.
(d) Zr and Ti are purified by Van Arkel method.
Correct Option: , 4
(a) $\mathrm{CaCO}_{3} \stackrel{\Delta}{\longrightarrow} \mathrm{CaO}+\mathrm{CO}_{2}$ \{In Blast furnace\} lime stone
(b) Ag form cyanide complex $\left[\mathrm{Ag}(\mathrm{CN})_{2}\right]^{-}$ during cyaride process
$\mathrm{Ag} / \mathrm{Ag}_{2} \mathrm{~S}+\mathrm{CN}^{\ominus} \rightarrow\left[\mathrm{Ag}(\mathrm{CN})_{2}\right]^{-}$
(c) $\mathrm{Ni}$ is purified by mond's process
(d) $\mathrm{Zr}$ and $\mathrm{Ti}$ are purified by van arkel method
All (a), (b), (c), (d) are correct statements Thus correct option is (4)