Question

Which one of the following oxides is neutral ?

• A. CO
• B. $SnO_2$
• C. ZnO
• D. $SiO_2$

Answer 1

Answer: (A)

CO

Answer 2

Carbon monoxide is a neutral oxide, all others are amphoteric:
$SnO_2 + 4HCI \longrightarrow SnCI_4 + 2H_2O$
$ZnO + 2HCI \longrightarrow ZnCI_2 + H_2O$
$SiO_2 + 2NaOH \longrightarrow Na_2SiO_3 + H_2O$
$SnO_2$ and ZnO also react with NaOH. $SiO_2$ is also attacked by $H_3PO_4$.