The energy required to break one mole of Cl–Cl bonds in Cl₂ is 242 kJ mol⁻¹. The largest wavelength of light capable of breaking a single Cl–Cl bond is
0.700 nm
1.494 nm
2.596 nm
3.640 nm
Explanation
Energy per bond = 242 × 10³ / (6.022 × 10²³) = 4.02 × 10⁻¹⁹ J. λ = hc/E = (6.626 × 10⁻³⁴ × 3 × 10⁸) / 4.02 × 10⁻¹⁹ ≈ 494 nm