JEE Mains · Chemistry · STD 11 - 5. Thermodynamics and thermochemistry
The heat of atomization of methane and ethane are \(360\,kJ/mol\) and \(620\,kJ/mol,\) respectively. The longest wavelength of light capable of breaking the \(C - C\) bond is (Avogadro number \(= 6.02 \times 10^{23},\) \(h = 6.62 \times 10^{-34}\,Js\) )
- A \(2.48 \times 10^4\,\,nm\)
- B \(1.49 \times 10^3\,\,nm\)
- C \(2.48 \times 10^3\,\,nm\)
- D \(1.49 \times 10^4\,\,nm\)
Answer & Solution
Correct Answer
(B) \(1.49 \times 10^3\,\,nm\)
Step-by-step Solution
Detailed explanation
In \(C{H_4},\,4 \times B{E_{(C - H)}} = 360\,kJ/mol\) \(\therefore \,B{E_{(C - H)}} = 90{\kern 1pt} kJ/mol\) In \({C_2}{H_6},\,B{E_{(C - C)}} + 6 \times B{E_{(C - H)}} = 620\,kJ/mol\) \(\therefore \,B{E_{(C - C)}} = 80{\kern 1pt} kJ/mol\)…
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