In the following sets of resonating structure, lable the major and minor contributors towards resonance hybrid.
`(P)underset("(I)")(CH_(3)-overset(Theta)CH-C-=N)harrunderset("(II)")(CH_(3)CH=C=overset(..)N:^(Theta))" (Q)"underset("(I)")(CH_(3)-overset(Theta)CH-CH=CH-NO)harrunderset("(II)")(CH_(3)-CH=CH-CH=overset(o+)underset(O^(Theta))underset(|)N-O^(Theta))`
`(R)underset("(I)")(CH_(3)-CH_(2)-overset(o+)underset(""NH_(2))underset(|)(C)-NH_(2))harrunderset("(II)")(CH_(3)-CH_(2)-underset(""NH_(2))underset(|)(C)=overset(o+)NH_(2))" (S)"underset("(I)")(CH_(3)-overset(O)overset(||)C-overset(Theta)CH-overset(O)overset(||)C-CH_(3))harrunderset("(II)")(CH_(3)-overset(O^(Theta))overset(|)C=CH-overset(O)overset(||)C-CH_(3)`

Answer

To determine the major and minor contributors to the resonance hybrid for each part of the question, we will analyze the stability of the given resonance structures based on the following criteria:

1. **Number of Charges**: Fewer charges generally lead to greater stability.
2. **Charge Location**: Negative charges should ideally be on more electronegative atoms.
3. **Number of Pi Bonds**: More pi bonds generally indicate greater stability.

Let's analyze each part step by step:

### Part P
1. **Structures**:
- Structure I: \( CH_3-CH^{-}-C \equiv N \)
- Structure II: \( CH_3-CH=C=N^{-} \)

2. **Analysis**:
- Both structures have one charge.
- Both structures have two pi bonds.
- In Structure I, the negative charge is on carbon, while in Structure II, it is on nitrogen. Since nitrogen is more electronegative than carbon, Structure II is more stable.

3. **Conclusion**:
- **Major Contributor**: Structure II
- **Minor Contributor**: Structure I

### Part Q
1. **Structures**:
- Structure I: \( CH_3-CH^{-}-CH=CH-NO \)
- Structure II: \( CH_3-CH=CH-CH=N^{+}O^{-}O^{-} \)

2. **Analysis**:
- Structure I has one charge, while Structure II has three charges.
- Fewer charges indicate greater stability, so Structure I is more stable than Structure II.

3. **Conclusion**:
- **Major Contributor**: Structure I
- **Minor Contributor**: Structure II

### Part R
1. **Structures**:
- Structure I: \( CH_3-CH_2-C^{+}-NH_2 \)
- Structure II: \( CH_3-CH_2-C-NH_2=NH_2^{+} \)

2. **Analysis**:
- Both structures have one charge.
- Structure I has no pi bonds, while Structure II has one pi bond.
- More pi bonds indicate greater stability, so Structure II is more stable.

3. **Conclusion**:
- **Major Contributor**: Structure II
- **Minor Contributor**: Structure I

### Part S
1. **Structures**:
- Structure I: \( CH_3-C=O-CH^{-}-C=O-CH_3 \)
- Structure II: \( CH_3-C=O^{-}-CH=C=O-CH_3 \)

2. **Analysis**:
- Both structures have one charge.
- Both structures have two pi bonds.
- In Structure I, the negative charge is on carbon, while in Structure II, it is on oxygen. Since oxygen is more electronegative than carbon, Structure II is more stable.

3. **Conclusion**:
- **Major Contributor**: Structure II
- **Minor Contributor**: Structure I

### Summary of Contributors
- **Part P**: Major II, Minor I
- **Part Q**: Major I, Minor II
- **Part R**: Major II, Minor I
- **Part S**: Major II, Minor I