The combustion of Li, Na, K in excess of air gives major oxides

Options

A. `Li_2O , Na_2O and K_2O_2`
B. `Li_2O , Na_2O_2 and K_2O`
C. `Li_2O , Na_2O_2 and KO_2`
D. `Li_2O_2 , Na_2O_2 and K_2O_2`

Answer

To solve the question regarding the combustion of Lithium (Li), Sodium (Na), and Potassium (K) in excess air and the major oxides they form, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Elements**: We are dealing with three alkali metals: Lithium (Li), Sodium (Na), and Potassium (K).

2. **Understand Combustion in Air**: Combustion in air means that these metals are reacting with oxygen (O₂) present in the atmosphere.

3. **Reaction of Lithium with Oxygen**:
- When Lithium combusts in excess air, it reacts with oxygen to form Lithium Oxide.
- The balanced chemical equation for this reaction is:
\[ 4Li + O_2 \rightarrow 2Li_2O \]
- The major oxide formed is Lithium Oxide (Li₂O).

4. **Reaction of Sodium with Oxygen**:
- Sodium reacts with oxygen to form Sodium Peroxide.
- The balanced chemical equation for this reaction is:
\[ 4Na + O_2 \rightarrow 2Na_2O_2 \]
- The major oxide formed is Sodium Peroxide (Na₂O₂).

5. **Reaction of Potassium with Oxygen**:
- Potassium reacts with oxygen to form Potassium Superoxide.
- The balanced chemical equation for this reaction is:
\[ 4K + O_2 \rightarrow 2K_2O_2 \]
- The major oxide formed is Potassium Superoxide (KO₂).

6. **Summary of Major Oxides**:
- Lithium (Li) forms Lithium Oxide (Li₂O).
- Sodium (Na) forms Sodium Peroxide (Na₂O₂).
- Potassium (K) forms Potassium Superoxide (KO₂).

### Final Answer:
- The major oxides formed from the combustion of Lithium, Sodium, and Potassium in excess air are:
- Lithium: Lithium Oxide (Li₂O)
- Sodium: Sodium Peroxide (Na₂O₂)
- Potassium: Potassium Superoxide (KO₂)