Question

The energy required to break one mole of Cl–Cl bonds in Cl₂ is 242 kJ mol^–1. The longest wavelength of light capable of breaking a single Cl – Cl bond is (c = 3 x 10⁸ ms^–1 and NA = 6.02 x 10²³ mol^–1)

(1) 594 nm 

(2) 640 nm 

(3) 700 nm 

(4) 494 nm

Answer 1

(4)

Energy required for 1 Cl₂ molecule = (242x10³)/N_A) (242x10³) Joules.