Determine the hybridization and geometry around the indicated carbon atoms. H3C CH3 – A B. CH2 CH3
Carbon A is:
O sp hybridized
O sp2 hybridized
O trigonal planar
O tetrahedral
O linear
The Correct Answer And Explanation is:
Let’s analyze the molecule given:
Molecular structure (simplified):
H₃C–CH₃ — A — B — CH₂–CH₃
To determine the hybridization and geometry of carbon A, we need to understand the structure and bonding of carbon atoms.
Step 1: Understand Carbon’s Valency
Carbon forms 4 bonds in stable organic compounds. The hybridization and geometry depend on how many atoms or groups are bonded to carbon and whether there are any double or triple bonds.
- sp³ hybridization occurs when carbon forms 4 single bonds (tetrahedral geometry, ~109.5°).
- sp² hybridization occurs when carbon is double bonded to one atom and forms two single bonds with others (trigonal planar, ~120°).
- sp hybridization occurs when carbon forms a triple bond or two double bonds (linear geometry, 180°).
Step 2: Analyze Carbon A
The description suggests a chain:
H₃C–CH₃ — A — B — CH₂–CH₃
If we break this down, we see:
- CH₃–CH₃ is ethane (two methyl groups).
- Then there’s a carbon labeled A, bonded to the second methyl group and to carbon B.
- Carbon B is then bonded to an ethyl group (CH₂–CH₃).
So carbon A is:
- Bonded to carbon on the left (a CH₃ group)
- Bonded to carbon B on the right
- And likely has two hydrogen atoms to satisfy the four-bond rule
This results in four single bonds.
Step 3: Determine Hybridization and Geometry
Since carbon A forms four sigma bonds (no double/triple bonds), it is:
- sp³ hybridized
- Tetrahedral in geometry
This geometry allows for bond angles of approximately 109.5°, typical for sp³-hybridized carbon atoms.
Final Answer:
✅ Carbon A is:
- sp³ hybridized
- Tetrahedral
Incorrect Options Explained:
- sp hybridized → Only if there are two double bonds or a triple bond (not present here).
- sp² hybridized → Requires a double bond.
- Trigonal planar → Related to sp² hybridization.
- Linear → Related to sp hybridization.
Thus, the correct answer is:
✅ sp³ hybridized and tetrahedral