Question

Consider the following statements.
(a) Mixture of $CO$ and $N_2$ is called synthesis gas.
(b) $CO$ reduces both $F{e}_2{O}_3$ and $ZnO$ to their respective metals.
(c) $CO$ is a $\pi$ acid ligand.
The correct statements are:

• A. (a) and (b) only
• B. (b) and (c) only
• C. (a) and (c) only
• D. (a), (b) and (c)

Answer 1

The correct option is B (b) and (c) only

• Mixture of $CO$ and $N_2$ is called producer gas.
• $CO$ reduces both $F{e}_2{O}_3$ and $ZnO$.

${\mathrm{Fe}}_2{O}_3\left(s\right)+3\mathrm{CO}\left(g\right)\stackrel{\Delta }{\to }2\mathrm{Fe}\left(s\right)+3{\mathrm{CO}}_2\left(g\right)\mathrm{ZnO}\left(s\right)+\mathrm{CO}\left(g\right)\stackrel{\Delta }{\to }\mathrm{Zn}\left(s\right)+{\mathrm{CO}}_2\left(g\right)$

• $CO$ is $\sigma$ donor and $\pi$ acceptor. It accepts electrons to the $\pi$ anti-bonding molecular orbital from filled d orbital of metal. Hence it is called as $\pi$-acid ligand.