Find the number of `1^(@),2^(@)` & `3^(@)` hydrogen atom in the following compounds
(a)`CH_(3)-undersetunderset(CH_(3))(|)(CH)-CH_(3)` , (b)`CH_(3)-CH_(2)-CH_(3)` , ( c)`CH_(3)-CH_(2)-CH_(2)-CH_(3)`

Answer

To find the number of 1°, 2°, and 3° hydrogen atoms in the given compounds, we first need to understand what these terms mean:

- **1° (Primary) hydrogen atoms** are attached to primary carbon atoms. A primary carbon is one that is attached to only one other carbon atom.
- **2° (Secondary) hydrogen atoms** are attached to secondary carbon atoms. A secondary carbon is one that is attached to two other carbon atoms.
- **3° (Tertiary) hydrogen atoms** are attached to tertiary carbon atoms. A tertiary carbon is one that is attached to three other carbon atoms.

Now, let's analyze each compound step by step:

### (a) CH₃-CH(CH₃)-CH₃
1. **Identify the carbon types:**
- The leftmost carbon (C1) is a primary carbon (1°).
- The middle carbon (C2) is a tertiary carbon (3°) because it is connected to three other carbon atoms (C1, C3, and C4).
- The rightmost carbon (C3) is also a primary carbon (1°).

2. **Count the hydrogen atoms:**
- **1° hydrogen atoms:** Each primary carbon has 3 hydrogen atoms. There are 2 primary carbons, so 2 × 3 = 6 hydrogen atoms.
- **2° hydrogen atoms:** The secondary carbon (C2) has no hydrogen atoms because it is fully substituted.
- **3° hydrogen atoms:** The tertiary carbon (C2) has 1 hydrogen atom.

**Total for (a):**
- 1° hydrogen: 6
- 2° hydrogen: 0
- 3° hydrogen: 1

### (b) CH₃-CH₂-CH₃
1. **Identify the carbon types:**
- The leftmost carbon (C1) is a primary carbon (1°).
- The middle carbon (C2) is a secondary carbon (2°).
- The rightmost carbon (C3) is also a primary carbon (1°).

2. **Count the hydrogen atoms:**
- **1° hydrogen atoms:** Each primary carbon has 3 hydrogen atoms. There are 2 primary carbons, so 2 × 3 = 6 hydrogen atoms.
- **2° hydrogen atoms:** The secondary carbon (C2) has 2 hydrogen atoms.
- **3° hydrogen atoms:** There are no tertiary carbons.

**Total for (b):**
- 1° hydrogen: 6
- 2° hydrogen: 2
- 3° hydrogen: 0

### (c) CH₃-CH₂-CH₂-CH₃
1. **Identify the carbon types:**
- The leftmost carbon (C1) is a primary carbon (1°).
- The second carbon (C2) is a secondary carbon (2°).
- The third carbon (C3) is also a secondary carbon (2°).
- The rightmost carbon (C4) is a primary carbon (1°).

2. **Count the hydrogen atoms:**
- **1° hydrogen atoms:** Each primary carbon has 3 hydrogen atoms. There are 2 primary carbons, so 2 × 3 = 6 hydrogen atoms.
- **2° hydrogen atoms:** Each secondary carbon has 2 hydrogen atoms. There are 2 secondary carbons, so 2 × 2 = 4 hydrogen atoms.
- **3° hydrogen atoms:** There are no tertiary carbons.

**Total for (c):**
- 1° hydrogen: 6
- 2° hydrogen: 4
- 3° hydrogen: 0

### Final Summary:
- For (a): 1° H = 6, 2° H = 0, 3° H = 1
- For (b): 1° H = 6, 2° H = 2, 3° H = 0
- For (c): 1° H = 6, 2° H = 4, 3° H = 0