Note : Consider the following four compounds for answering questions 19 and 20.
I. `CH_3 - CH_2 - CH_2 - overset(overset(O)||)C - H`
II. `CH_3 - CH_2 - CH_2 - overset(overset(O)||) C - CH_3`
III. `CH_3 - CH_2 - underset(underset(O)||) C - CH_2 - CH_3`
IV. `CH_3 - underset(underset(CH_3)|)CH - CH_2 - underset(underset(O)||)C - H`
Hyperconjugation involves delocalisation of _________

Options

A. electrons of carbon-hydrogen `sigma` bond of an alkyl group directly attached to an atom of unsaturated system.
B. electrons of carbon-hydrogen o bond of alkyl group directly attach8d to the positively charged carbon atom.
C. `pi`- electrons of carbon-carbon bond
D. lone pair of electrons

Answer

To solve the question regarding hyperconjugation, we need to understand what hyperconjugation is and what it involves. Let's break it down step by step.

### Step-by-Step Solution:

1. **Understanding Hyperconjugation**:
Hyperconjugation is a concept in organic chemistry that refers to the delocalization of electrons in sigma bonds (specifically C-H bonds) with an adjacent empty or partially filled p-orbital or a pi bond.

2. **Identifying the Components**:
In the context of the question, we are looking at the delocalization of electrons from carbon-hydrogen (C-H) sigma bonds of alkyl groups that are directly attached to an unsaturated system (like a double bond or a positively charged carbon atom).

3. **Analyzing the Options**:
- **Option 1**: "Carbon hydrogen sigma bond of an alkyl group directly attached to an atom of unsaturated system."
- This is correct because the electrons from the C-H bond can be delocalized into the unsaturated system.

- **Option 2**: "Electron of carbon-hydrogen sigma bond of alkyl group directly attached to the positively charged carbon atom."
- This is also correct because the electrons from the C-H bond can stabilize a carbocation by delocalizing into the positively charged carbon atom.

- **Option 3**: "Pi electron of carbon-carbon bond."
- This is incorrect because hyperconjugation does not involve pi electrons; it specifically involves sigma electrons.

- **Option 4**: "Lone pair of electrons."
- This is also incorrect because hyperconjugation does not involve lone pairs; it involves the delocalization of sigma bond electrons.

4. **Conclusion**:
Based on the analysis, hyperconjugation involves the delocalization of electrons from the C-H sigma bonds of alkyl groups directly attached to either an unsaturated system or a positively charged carbon atom. Thus, the correct answers are options 1 and 2.

### Final Answer:
Hyperconjugation involves the delocalization of **sigma electrons from carbon-hydrogen bonds**.

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