Question

Which of the following is used in the extraction of metal from their oxide ores?

• A. CO
• B. $O_2$
• C. Both (a) and (b)
• D. None of the above

Answer 1

The correct option is A CO

CO is a colourless, odorless and water insoluble gas. It is a power reducing agent. Hence, it is used in the extraction of metals from their oxide's ores.
$F{e}_2{O}_3\left(s\right)+3CO\left(g\right)\stackrel{\Delta }{⟶}3C{O}_2\left(g\right)+2Fe\left(s\right)$
$ZnO\left(s\right)+CO\left(g\right)\stackrel{\Delta }{⟶}Zn\left(s\right)+C{O}_2\left(g\right)$

$O_2$ is an oxidising agent so it does not have this property.
THEORY
Properties:

• CO is a colorless, odorless, and almost water-insoluble gas.
• It is a powerful reducing agent. This property of CO is used in the extraction of many metals from their oxide ores.
• $F{e}_2{O}_3\left(s\right)+3CO\left(g\right)\stackrel{△}{\to }3C{O}_2\left(g\right)+2Fe\left(s\right)$
• $ZnO\left(s\right)+CO\left(g\right)\stackrel{△}{\to }Zn\left(s\right)+C{O}_2\left(g\right)$
• The molecule contains one sigma and two $\pi$ bonds between Carbon and Oxygen.
• Due to the presence of lone pair on C, CO acts as a donor and reacts with certain metals when heated to give metal carbonyls.
• The highly poisonous nature of CO arises because of its ability to form a complex with haemoglobin.

A CO-haemoglobin is about 300 times more stable than the O2-haemoglobin complex. This prevents haemoglobin in the red blood corpuscles from carrying oxygen around the body and ultimately resulting in death.