The energy required to break one mole of `Cl-Cl` bonds in `Cl_2` is `242 kJ mol^-1`. The longest wavelength of light capable of breaking a since `Cl-Cl` bond is

Options

A. 700 nm
B. 494 nm
C. 564 nm
D. 640 nm

Answer

B

Explanation

Bond energy of single bond`=(242)/(6.023xx10^(23))`
`=4.017xx10^(-22)kJ`
`=4.017xx10^(-19)J`
`E=(hc)/(lamda)`
`4.017xx10^(-19)=(6.626xx10^(-34)xx3xx10^(8))/(lamda)`
`lamda=4.94xx10^(-7)m=494`nm