The coeffcients in front of the elements, represent moles. Therefore because the equation is balanced, you would evaluate your answer of the mole based off of what the question is asking. The question asked about the mole ratio of the two elements HCl to VOCL3. There is a number 6 in front of HCl which means that there are 6 moles of HCl, and there is a 2 in front of VOCL3 which means that there are 2 moles of VOCL3.
Therefore the correct answer will be 6 HCl to 2 VOCL3
The lighter components are able to rise higher in the column before they are cooled to their condensing temperature, allowing them to be removed at slightly higher levels.
