Q6(c)(ii). Quantum yield of photobromination
Photobromination of cinnamic acid was carried out using light of wavelength 480 nm with a light intensity of 1.5 × 10⁻³ J s⁻¹. An exposure of 10 minutes showed a decrease of 0.05 millimole of Br₂. Calculate the quantum yield assuming that 80% of radiation is absorbed by cinnamic acid. (Planck's constant h = 6.627 × 10⁻³⁴ J s and velocity of light c = 3 × 10⁸ m s⁻¹)
Answer in brief
Φ = 17.3.
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All parts of Question 6
- 6(a)(i) Products and intermediates of two reductions10 marks
- 6(a)(ii) Role of NMO in catalytic dihydroxylation5 marks
- 6(b) Three numericals15 marks
- 6(c)(i) Benzene to fulvene by light5 marks
- 6(c)(ii) Quantum yield of photobromination5 marks
- 6(c)(iii) Photolysis of 4,5-dimethylhexan-2-one5 marks
- 6(c)(iv) A, B and C from the mixed ketones5 marks