Answer :
Sure, let's analyze each molecule to determine the bonding pairs and lone pairs of electrons.
### A. C[tex]\(_2\)[/tex]H[tex]\(_4\)[/tex] (Ethene)
1. Structure of Ethene (C[tex]\(_2\)[/tex]H[tex]\(_4\)[/tex]):
- Each carbon (C) atom forms 3 sigma bonds: 2 with hydrogen (H) atoms and 1 with the other carbon (C) atom.
- Furthermore, there is one π (pi) bond between the two carbon atoms.
2. Counting the Bonding Pairs:
- Each carbon-hydrogen bond is a single bond (σ bond), so there are 4 C-H bonds.
- There is one C-C σ bond and one C-C π bond (which count as one bonding pair in terms of electron pairs).
Therefore, the total number of bonding pairs is the sum of:
- 4 C-H bonds (4 pairs)
- 1 C-C σ bond (1 pair)
- 1 C-C π bond (1 pair)
Total bonding pairs = 6 pairs.
3. Counting the Lone Pairs:
- Hydrogen atoms do not have lone pairs.
- Carbon in ethene has no lone pairs on each atom.
Total lone pairs = 0.
So the C[tex]\(_2\)[/tex]H[tex]\(_4\)[/tex] molecule has:
- 6 bonding pairs of electrons.
- 0 lone pairs of electrons.
### B. C[tex]\(_2\)[/tex]H[tex]\(_2\)[/tex] (Ethyne or Acetylene)
1. Structure of Ethyne (C[tex]\(_2\)[/tex]H[tex]\(_2\)[/tex]):
- Each carbon (C) atom forms 2 types of bonds: one σ bond with a hydrogen (H) atom, and a triple bond (one σ bond and two π bonds) with the other carbon (C) atom.
2. Counting the Bonding Pairs:
- Each carbon-hydrogen bond is a single bond (σ bond), so there are 2 C-H bonds.
- The triple bond between carbon atoms consists of one σ bond and two π bonds (which together count as one high-order bond).
Therefore, the total number of bonding pairs is the sum of:
- 2 C-H bonds (2 pairs)
- 1 C-C triple bond (1 pair for σ bond + 2 pairs for π bonds
Total bonding pairs = 5 pairs.
3. Counting the Lone Pairs:
- Hydrogen atoms do not have lone pairs.
- Each carbon atom in ethyne has no lone pairs.
Total lone pairs = 0.
So the C[tex]\(_2\)[/tex]H[tex]\(_2\)[/tex] molecule has:
- 5 bonding pairs of electrons.
- 0 lone pairs of electrons.
### Summary:
- C[tex]\(_2\)[/tex]H[tex]\(_4\)[/tex]: 6 bonding pairs, 0 lone pairs.
- C[tex]\(_2\)[/tex]H[tex]\(_2\)[/tex]: 5 bonding pairs, 0 lone pairs.
### A. C[tex]\(_2\)[/tex]H[tex]\(_4\)[/tex] (Ethene)
1. Structure of Ethene (C[tex]\(_2\)[/tex]H[tex]\(_4\)[/tex]):
- Each carbon (C) atom forms 3 sigma bonds: 2 with hydrogen (H) atoms and 1 with the other carbon (C) atom.
- Furthermore, there is one π (pi) bond between the two carbon atoms.
2. Counting the Bonding Pairs:
- Each carbon-hydrogen bond is a single bond (σ bond), so there are 4 C-H bonds.
- There is one C-C σ bond and one C-C π bond (which count as one bonding pair in terms of electron pairs).
Therefore, the total number of bonding pairs is the sum of:
- 4 C-H bonds (4 pairs)
- 1 C-C σ bond (1 pair)
- 1 C-C π bond (1 pair)
Total bonding pairs = 6 pairs.
3. Counting the Lone Pairs:
- Hydrogen atoms do not have lone pairs.
- Carbon in ethene has no lone pairs on each atom.
Total lone pairs = 0.
So the C[tex]\(_2\)[/tex]H[tex]\(_4\)[/tex] molecule has:
- 6 bonding pairs of electrons.
- 0 lone pairs of electrons.
### B. C[tex]\(_2\)[/tex]H[tex]\(_2\)[/tex] (Ethyne or Acetylene)
1. Structure of Ethyne (C[tex]\(_2\)[/tex]H[tex]\(_2\)[/tex]):
- Each carbon (C) atom forms 2 types of bonds: one σ bond with a hydrogen (H) atom, and a triple bond (one σ bond and two π bonds) with the other carbon (C) atom.
2. Counting the Bonding Pairs:
- Each carbon-hydrogen bond is a single bond (σ bond), so there are 2 C-H bonds.
- The triple bond between carbon atoms consists of one σ bond and two π bonds (which together count as one high-order bond).
Therefore, the total number of bonding pairs is the sum of:
- 2 C-H bonds (2 pairs)
- 1 C-C triple bond (1 pair for σ bond + 2 pairs for π bonds
Total bonding pairs = 5 pairs.
3. Counting the Lone Pairs:
- Hydrogen atoms do not have lone pairs.
- Each carbon atom in ethyne has no lone pairs.
Total lone pairs = 0.
So the C[tex]\(_2\)[/tex]H[tex]\(_2\)[/tex] molecule has:
- 5 bonding pairs of electrons.
- 0 lone pairs of electrons.
### Summary:
- C[tex]\(_2\)[/tex]H[tex]\(_4\)[/tex]: 6 bonding pairs, 0 lone pairs.
- C[tex]\(_2\)[/tex]H[tex]\(_2\)[/tex]: 5 bonding pairs, 0 lone pairs.
