Question

2 multiple choice 2 points how many σ bonds does the compound shown contain?
chemical structure image
○ 3
○ 9
○ 5
○ 10

Explanation:

Step1: Analyze single bonds (all σ) and double bond (1 σ)

• Single bonds: \( \ce{C - CH_3} \) (2 bonds), \( \ce{C - N} \) (1 bond), \( \ce{N - H} \) (1 bond), \( \ce{CH_3} \) has 3 \( \ce{C - H} \) each, so \( 2\times3 = 6 \) \( \ce{C - H} \) bonds.
• Double bond (\( \ce{C\equiv N} \)? Wait, no, the structure is \( \ce{C = N} \) (double bond: 1 σ, 1 π). Wait, re - examine: The central C is bonded to two \( \ce{CH_3} \) (each \( \ce{CH_3} \) has 3 C - H bonds), 1 N (with a double bond: C = N, so 1 σ here), and N is bonded to 1 H.

Wait, let's count all σ bonds:

• \( \ce{C - CH_3} \): 2 bonds (σ)
• \( \ce{CH_3} \) groups: each has 3 \( \ce{C - H} \) bonds, so \( 2\times3=6 \) (σ)
• \( \ce{C - N} \): 1 bond (σ, part of the double bond, the other is π)
• \( \ce{N - H} \): 1 bond (σ)

Total: \( 2 + 6+1 + 1=10 \)? Wait, no, wait the double bond is C = N, so in a double bond, there is 1 σ and 1 π. Let's list all bonds:

1. \( \ce{C - CH_3} \) (2 bonds, σ)
2. \( \ce{CH_3} \) - C: each \( \ce{CH_3} \) has 3 \( \ce{C - H} \), so 2 \( \ce{CH_3} \) gives 6 \( \ce{C - H} \) (σ)
3. \( \ce{C = N} \): 1 σ bond
4. \( \ce{N - H} \): 1 σ bond

Wait, but maybe I made a mistake. Wait the central C: bonded to two \( \ce{CH_3} \) (so 2 C - C bonds, σ), two \( \ce{CH_3} \) have 3 H each, so 6 C - H (σ). Then C is bonded to N with a double bond (1 σ, 1 π). N is bonded to H (1 σ). So total σ bonds: 2 (C - C) + 6 (C - H) + 1 (C - N) + 1 (N - H) = 10? Wait no, wait the double bond is C = N, so C - N is 1 σ, and the other bond in double is π. Wait let's count again:

• Bonds from \( \ce{CH_3} \): Each \( \ce{CH_3} \) has 3 C - H bonds. There are two \( \ce{CH_3} \) groups, so \( 2\times3 = 6 \) C - H σ bonds.
• Bonds from C to \( \ce{CH_3} \): 2 C - C σ bonds.
• Bond from C to N: 1 C - N σ bond (since the double bond has 1 σ and 1 π)
• Bond from N to H: 1 N - H σ bond.

Now sum them up: \( 6+2 + 1+1=10 \)? Wait but the options have 10 as an option. Wait maybe my initial analysis was wrong. Wait let's draw the structure:

Central carbon (C) is bonded to two \( \ce{CH_3} \) (so two C - C single bonds, σ), one N (with a double bond: C = N, so one σ bond between C and N), and N is bonded to one H (N - H, σ). Each \( \ce{CH_3} \) has three C - H bonds (σ). So:

• C - C: 2
• C - H: 2 \( \times \) 3 = 6
• C - N: 1 (σ part of double bond)
• N - H: 1

Total: 2 + 6+1 + 1 = 10.

Step2: Verify the count

Wait, maybe I miscounted. Let's list each bond:

1. \( \ce{CH_3 - C} \) (σ)
2. \( \ce{CH_3 - C} \) (σ)
3. \( \ce{C - H} \) in first \( \ce{CH_3} \): 3 (σ)
4. \( \ce{C - H} \) in second \( \ce{CH_3} \): 3 (σ)
5. \( \ce{C - N} \) (σ, part of C = N)
6. \( \ce{N - H} \) (σ)

Wait, that's 2 (C - C) + 6 (C - H) + 1 (C - N) + 1 (N - H) = 10. So the number of σ bonds is 10.

Answer:

10 (the option with 10)