Verified Solution • 2025–26 Session moderate

QJEEM10Chf0e2: JEE Main 2010 Chemistry - Class 11 JEEM10Chf0e2 Solution: The energy required to break one mole of Cl–Cl bonds in Cl 2 is …

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)

Multiple Choice Options

  • A 594 nm
  • B 640 nm
  • C 700 nm
  • D 494 nm

Step-by-Step Verified Solution

Energy required to break one Cl2 molecule = 242×1036.02×1023{{242 \times {{10}^3}} \over {6.02 \times {{10}^{23}}}} J

As E = hcλ{{hc} \over \lambda }

So λ=hcE\lambda = {{hc} \over E}

= 6.626×10−34×3×108×6.02×1023242×103{{6.626 \times {{10}^{ - 34}} \times 3 \times {{10}^8} \times 6.02 \times {{10}^{23}}} \over {242 \times {{10}^3}}}

= 494 ×\times 10-9 m

= 494 nm

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