Question

Which of the following oxides are acidic ?
$\text{CuO,} \, \text{Mn}_{\text{2}} \text{O}_{\text{7}} \text{,} \, \text{CO,} \, \text{SO}_{\text{2}} \text{,} \, \text{CrO}_{\text{3}}$

• A. $\text{CrO}_{\text{3}} \text{,} \, \text{Mn}_{\text{2}} \text{O}_{\text{7}}$ and $\text{SO}_{2}$
• B. Only $\text{SO}_{2}$
• C. $\text{Mn}_{\text{2}} \text{O}_{\text{7}}$ and $\text{SO}_{2}$
• D. $\text{CO}$ and $\text{SO}_{2}$

Answer 1

Answer: (A)

$\text{C} \text{u} \text{O}$ is basic oxide and $\text{C} \text{O}$ is neutral oxide.
$\text{CrO}_{3} + \text{H}_{2} \text{O} \rightarrow \underset{\text{Acid}}{\text{H}_{2} \text{CrO}_{4}}$
$\left(\text{SO}\right)_{2}+\left(\text{H}\right)_{2}\text{O} & \rightarrow & \left(\text{H}\right)_{2}\left(\text{SO}\right)_{3} & \left(\text{acid}\right) \\ \left(\text{Mn}\right)_{2}\left(\text{O}\right)_{7}+\left(\text{H}\right)_{2}\text{O} & \rightarrow & 2\left(\text{HMnO}\right)_{4} & \left(\text{acid}\right)$