How does impure Ni is purified ?

Options

A. Impure `Ni + CO_(2) rarr NiCO_(3)NiO + CO_2Ni`
B. Impure `Ni+CONi(CO)_6 rarr "gaseous" Ni(g) +CO(g)+Ni(s)"pure"`
C. Impure `Ni + CONi(CO)_4 rarr Ni(s) + CO(s)`
D. Impure ` Ni+CO rarr Ni(CO)_4(g) overset(Delta) rarr Ni(s) + CO(g)`

Answer

D

Explanation

Impure ` Ni+CO rarr Ni(CO)_4(g) overset(Delta) rarr Ni(s) + CO(g)`