Question 18.1.3: 1 × 10^-4 mole of a substance decomposed when it was irradia......

Quantum efficiency of the reaction = 8

Number of moles decomposed = 1 × 10^{–4}

Number of molecules decomposed = 1 × 10^{–4} × 6.023 × 1023 = 6.023 × 10^{19}

Quantum yield Φ= \frac{\text{Number of molecules decomposed}}{\text{Number of photons absorbed}}

∴ Number of photons absorbed =\frac{6.023× 10^{19}}{ \text{Quantum yield}  Φ}=\frac{6.023 ×10^{19}}{8}= 7.528 ×10^{18}