1. Tardigrade
  2. Question
  3. Chemistry
  4. At 730° C the vapor density of iodine under a pressure of 1 atm is 97.45 % of the theoretical, on the assumption that the molecule of gaseous iodine is diatomic. What is the degree of dissociation of I2 ?

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Q. At $730^{\circ} C$ the vapor density of iodine under a pressure of $1$ atm is $97.45 \%$ of the theoretical, on the assumption that the molecule of gaseous iodine is diatomic. What is the degree of dissociation of $I_{2}$ ?

Equilibrium

Solution:

van't Hoff factor

$i=\frac{\text { Theoretical value of mol. wt. }}{\text { Observed value of mol. wt. }}$

image

Total number of moles at equilibrium $=1-\alpha+2 \alpha=1+\alpha$

$i=\frac{1+\alpha}{1} ; \frac{254}{247.52}=1+\alpha$

or $247.52 \alpha=254-247.52=6.48.$

$\alpha=\frac{6.48}{247.52}=0.0262$