Problems and exercisesConstitution of Organic Compounds

1. Hybridization

State the hybridization of each carbon, nitrogen and oxygen atom in these molecules:

1. CH₃–CH=CH₂
2. CH₃–C≡N
3. CH₃–CHO
4. CH₂=C=CH₂
5. CH₃–NH₂
6. O=C=O

2. Geometry and bond angles

For each molecule, state how many electron densities surround the central atom (C, N or O), its hybridization, the geometry of the molecule around that atom and the approximate bond angle:

CH₄  ·  NH₃  ·  H₂O  ·  H₂C=O  ·  HC≡CH  ·  HC≡N

3. σ and π bonds

Count the σ (sigma) and π (pi) bonds in each molecule:

1. CH₂=CH–CH₃
2. CH₃–C≡N
3. CH₃–COOH
4. CH₂=CH–C≡N

4. Where are the lone pairs?

State in which type of orbital the unshared electron pairs of the heteroatom (O or N) are found in each molecule:

1. CH₃–OH
2. CH₃–NH₂
3. H₂C=O
4. HC≡N

5. Electron densities

Complete the table:

6. True or false?

Decide whether these statements are true or false, giving your reasons:

1. A carbon bonded to four atoms is always sp³ hybridized.
2. In water, oxygen is sp hybridized because it is bonded to only two atoms.
3. A double bond consists of two σ bonds.
4. The H–N–H angle in ammonia is smaller than the H–C–H angle in methane.
5. In ethene, all six atoms lie in the same plane.