JEE Mains · Chemistry · STD 11 - 5. Thermodynamics and thermochemistry
The heat of atomisation of methane and ethane are 'x' kJ \(mol^{-1}\) and 'y' kJ \(mol^{-1}\) respectively. The longest wavelength (\(\lambda\)) of light capable of breaking the C - C bond can be expressed in SI unit as :
- A \(\frac{hc}{1000}(\frac{y-6x}{4})^{-1}\)
- B \(\frac{N_{A}hc}{250(4y-6x)}\)
- C \(\frac{N_{A}hc}{250(y-6x)}\)
- D \(N_{A}hc(y-\frac{6x}{4})^{-1}\)
Answer & Solution
Correct Answer
(B) \(\frac{N_{A}hc}{250(4y-6x)}\)
Step-by-step Solution
Detailed explanation
\(CH _4(g) \rightarrow C ( g )+4 H ( g ) ; \quad \Delta_{ r } H = x kJ / mole\) \(C _2 H _6(g) \rightarrow 2 C ( g )+6 H ( g ) ; \Delta_{ r } H = y kJ / mole\) \(1000 x =4 \times \varepsilon_{ C - H }\) \(1000 y =1 \times \varepsilon_{ C - C }+6 \times \varepsilon_{ C - H }\)…
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