JEE Chemistry 2023 Question with Solution

Given: The reaction is the water-gas shift reaction.

Find: Which statement is correct for this reaction.

The water-gas shift reaction is:

$$\mathrm{CO + H_2O \rightarrow CO_2 + H_2}$$

Now compare the oxidation state of carbon. In $\mathrm{CO}$, carbon is $+2$, while in $\mathrm{CO_2}$, carbon is $+4$. So carbon in carbon monoxide undergoes oxidation.

Thus, carbon monoxide is oxidized to carbon dioxide. Therefore, the correct option is B.

Given: Water-gas shift reaction.

Find: The correct statement among the four options.

1. Write the reaction:

$$\mathrm{CO + H_2O \rightarrow CO_2 + H_2}$$

2. Check oxidation state change of carbon:

• In $\mathrm{CO}$, carbon is $+2$.
• In $\mathrm{CO_2}$, carbon is $+4$.

3. Since the oxidation state increases from $+2$ to $+4$, $\mathrm{CO}$ is oxidized.
4. Hence option B is correct.

Why others are wrong:

• A: Carbon is not oxidized to carbon monoxide in this reaction.
• C: Carbon dioxide is formed, not reduced to carbon monoxide.
• D: Water reacts chemically; it is not merely evaporated.

Therefore, the correct option is B.