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 single Cl-Cl bond is
`(c=3xx10^(8) ms^(-1) and N_(A)=6.02xx10^(23) " mol"^(-1))`

Options

A. 594 mm
B. 640 mm
C. 700 mm
D. 494 mm

Answer

D

Explanation

Energy required to break one mole of Cl-Cl bonds in `Cl_(2)`
`=(242xx10^(3))/(6.023xx10^(23))=(hc)/(lamda)=(6.626xx10^(-34)xx3xx10^(8))/(lamda)`
`therefore lamda=(6.626xx10^(-34)xx3xx10^(8)xx6.023xx10^(23))/(242xx10^(3))`
`=0.4947xx10^(-6)m=494.7 nm`