Atomic Structure - Result Question 103

####79. Iodine molecule dissociates into atoms after absorbing light to $4500 \AA$. If one quantum of radiation is absorbed by each molecule, calculate the kinetic energy of iodine atoms. (Bond energy of $I _2=240 kJ mol^{-1}$ )

(1995, 2M)

Show Answer

Answer:

Correct Answer: 79. $(660 nm)$

Solution:

  1. After breaking of the bond of $I _2$ molecule, the remaining energy would be distributed uniformly to iodine atoms as their kinetic energy, i.e.

$E($ energy of photon $)=$ Bond energy $+2 \times$ kinetic energy

$$ \begin{array}{rlrl} \Rightarrow & & \frac{6.625 \times 10^{-34} \times 3 \times 10^{8}}{4500 \times 10^{-10}} & =\frac{240 \times 10^{3}}{6.023 \times 10^{23}}+2 \times E _k \ \Rightarrow & E _k & =2.16 \times 10^{20} J / \text { atom } \end{array} $$



NCERT Chapter Video Solution

Dual Pane