Chemistry · 2026
JEE Main · 24 January 2026, Shift 2 · Q54
The heat of atomisation of methane and ethane are ' x ' kJ mol^-1 and ' y ' kJ mol^-1 respectively. The longest wavelength (λ) of light capable of…
The heat of atomisation of methane and ethane are ' x ' $\displaystyle \mathrm{kJ} \mathrm{mol}^{-1}$ and ' y ' $\displaystyle \mathrm{kJ} \mathrm{mol}^{-1}$ respectively. The longest wavelength $\displaystyle (\lambda)$ of light capable of breaking the $\displaystyle \mathrm{C}-\mathrm{C}$ bond can be expressed in SI unit as:
Official answer
From NTA’s final answer key for this paper.
(1)
$\displaystyle \frac{\mathrm{N}_{\mathrm{A}} \mathrm{hc}}{250(4 y-6 x)}$
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JEE Main 2026 Chemistry question, with the answer from NTA’s final answer key. Where our answers come from.