According to equation 1 mole of F₂ reacts with 1 mole of CaBr₂. So, As, 199.89 g CaBr₂ reacts with = 1 mole of F₂ Then, 2.67 g of CaBr₂ will react with = X mole of F₂ Solving for X, X = (2.67 g × 1 mole) ÷ 199.89 g
X = 0.0133 moles of F₂
Now, Covert moles of F₂ into Volume, Assuming it as Ideal gas, So, Acc. to Ideal Gas Equation
Actually the strength
of London dispersion forces highly depend on the total number of electrons and
the area in which they are spread. We can see clearly that iodine will have the
strongest LDF's, and hence, have the highest boiling point (and melting point).
This is also the reason why iodine is a solid at room temperature, bromine is liquid
and chlorine and fluorine are gases.