On exposure to air, alkali metals get tranished due to formation of oxides, hydroxides and carbonates on their surface. When heated
in air or oxygen they burn vigourously forming different types of
oxides depending upon the nature of the metal. The formation and stability of these metals can be explained on the basis of size of
alkali metal ion and the anion. Peroxides are colourless, while superoxides are coloured. The normal oxides are basic while
peroxides and superoxides act as oxidising agents.
`Na_(2)O_(2)` has light yellow colour. This is due to

Options

A. Presence of traces of `NaO_(2)`
B. Presence of unpaired electron in the molecule.
C. Presence of traces of `Na_(2)O`.
D. None of the above.

Explanation

To answer the question regarding the light yellow color of sodium peroxide (Na₂O₂), we will follow a step-by-step approach:

### Step 1: Understand the Composition of Sodium Peroxide
Sodium peroxide (Na₂O₂) is a compound formed when sodium reacts with oxygen. It consists of sodium ions (Na⁺) and peroxide ions (O₂²⁻).

**Hint:** Identify the components of sodium peroxide and their characteristics.

### Step 2: Color Properties of Peroxides and Superoxides
Generally, peroxides are colorless, while superoxides (like sodium superoxide, NaO₂) are colored due to the presence of unpaired electrons. The yellow color of superoxides is attributed to these unpaired electrons.

**Hint:** Recall the differences in color properties between peroxides and superoxides.

### Step 3: Analyze the Question
The question asks why Na₂O₂ has a light yellow color when peroxides are typically colorless. This suggests that there might be an impurity or a related compound affecting the color.

**Hint:** Consider the possibility of impurities or other related compounds that could influence the color.

### Step 4: Identify the Source of the Color
It is known that sodium peroxide can contain traces of sodium superoxide (NaO₂). The presence of even a small amount of NaO₂ can impart a light yellow color to Na₂O₂ due to the characteristics of the superoxide.

**Hint:** Think about how impurities can affect the overall appearance of a compound.

### Step 5: Conclusion
The light yellow color of sodium peroxide (Na₂O₂) is due to the presence of traces of sodium superoxide (NaO₂) within it. This small amount of NaO₂ contributes to the observed color despite Na₂O₂ being colorless in its pure form.

**Final Answer:** The light yellow color of Na₂O₂ is due to the presence of traces of NaO₂ (sodium superoxide).