Question

The number of amphoteric oxides in the following is \[ CO_2,\ GeO_2,\ SnO_2,\ PbO_2,\ CO,\ GeO,\ SnO,\ PbO \]

• A. 5
• B. 3
• C. 2
• D. 4

Hint:

Important NCERT trend: \[ GeO_2,\ SnO_2,\ PbO_2 \] are amphoteric oxides frequently asked in examinations.

Answer 1

The Correct Option is B

Step 1: Recall what amphoteric means.
An amphoteric oxide reacts with both acids and bases. So it can behave as an acid or a base depending on what it meets.
Step 2: Note the group trend.
In Group 14, going down the group the oxides change from acidic at the top to basic at the bottom, with some in the middle being amphoteric. Also, the higher oxidation state $+4$ oxides are more acidic, and the $+2$ oxides are more basic.
Step 3: Classify the carbon oxides.
$CO_2$ is acidic. $CO$ is a neutral oxide. Neither is amphoteric.
Step 4: Classify the +4 oxides.
$GeO_2$, $SnO_2$, and $PbO_2$ are all amphoteric. They each react with both acids and bases.
Step 5: Classify the +2 oxides.
$GeO$, $SnO$, and $PbO$ behave as basic oxides here, so they are not counted as amphoteric in this list.
Step 6: Count the amphoteric oxides.
The amphoteric ones are $GeO_2$, $SnO_2$, and $PbO_2$, giving a total of \[ \boxed{3} \]