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

Options

A. `Li_2O, Na_2O_2, KO_2`
B. `Li_2O_2, Na_2O, K_2O`
C. `Li_2O, NaO_2, KO_2`
D. `LiO_2, Na_2O_2, 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 formed, we can follow these steps:

### Step 1: Understand the combustion of Lithium
When Lithium is combusted in excess air, it reacts with oxygen to form Lithium Oxide (Li2O). This occurs because Lithium has a smaller ionic size, which limits its ability to react further with oxygen.

**Hint:** Remember that smaller metal ions tend to form stable oxides without further reactions.

### Step 2: Understand the combustion of Sodium
When Sodium is combusted in excess air, it primarily forms Sodium Peroxide (Na2O2). The larger size of Sodium compared to Lithium allows it to react with additional oxygen to form the peroxide.

**Hint:** Larger metal ions can stabilize larger anions like peroxides due to their weaker positive field.

### Step 3: Understand the combustion of Potassium
When Potassium is combusted in excess air, it forms Potassium Superoxide (KO2). The even larger size of Potassium allows it to react with even more oxygen, resulting in the formation of superoxide.

**Hint:** As the size of the metal ion increases, the ability to stabilize larger anions such as superoxides also increases.

### Step 4: Summarize the results
- Lithium (Li) combusts to form Lithium Oxide (Li2O).
- Sodium (Na) combusts to form Sodium Peroxide (Na2O2).
- Potassium (K) combusts to form Potassium Superoxide (KO2).

### Conclusion
Thus, the major oxides formed from the combustion of Lithium, Sodium, and Potassium in excess air are:
1. Lithium Oxide (Li2O)
2. Sodium Peroxide (Na2O2)
3. Potassium Superoxide (KO2)

**Final Answer:** Lithium Oxide, Sodium Peroxide, and Potassium Superoxide.