Amino acids and chirality

Question 1

The general formula of an alpha-amino acid

Answer 1

CH(NH2)(COOH)(R)

Question 2

why does benzene require a catalyst to react with bromine when phenol and cyclohexane don’t?
focus benzene

Answer 2

in benzene the electrons (pi bonds) are delocalised. so benzene has a lower electron density so cannot induce a dipole in Br2.

Question 3

why does benzene require a catalyst to react with bromine when phenol and cyclohexane don’t?
focus phenol

Answer 3

phenol has a lone pair of electrons from the oxygen partially delocalised into the ring so it has a higher charge density than benzene so can induce a dipole in Br2

Question 4

why does benzene require a catalyst to react with bromine when phenol and cyclohexane don’t?
focus cyclohexane

Answer 4

cyclohexane does not have delocalised electrons. all its electrons are localised therefore it has a greater charge density than phenol and benzene so can induce a dipole in Br2

Question 5

benzene structure

Answer 5

p-orbitals overlap above and below the ring to form π-bonds which are delocalised.
the ring is hexagonal planar with a 120* bond angle.
the C to C bonds have an intermediate-length between C-C and C=C
sigma bongs between C-C and C-H