Explain the following :
Alkyl iodides become darken on standing in presence of light.

Explanation

**Step-by-Step Solution:**

1. **Understanding Alkyl Iodides**: Alkyl iodides are organic compounds that contain iodine atoms bonded to carbon atoms. The general formula for alkyl iodides is R-I, where R represents an alkyl group and I represents iodine.

2. **Weak C-I Bond**: The bond between carbon and iodine (C-I) in alkyl iodides is relatively weak compared to other carbon-halogen bonds. This weakness is primarily due to the large atomic size of iodine, which results in a longer bond length and weaker bond strength.

3. **Role of Light**: When alkyl iodides are exposed to light, they undergo photochemical reactions. The energy from light can break the weak C-I bond, leading to the formation of free radicals.

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