5J #5 part d

[Bailey Giovanoli 1L]

In question 5 of section 5J it asks you to identify whether products or reactants are favored if total pressure is increased. From what I gathered with Le Chatelier’s principle, if total pressure is increased, the side of the reaction with less moles will be favored. I think this is because if there are more moles on one side and pressure is increased the interaction between those molecules will increase due to less space to more freely. However, I am confused because part d gives the following reaction:
2HD (g) + H2-><- D2
I’m first concerned as to how the Hydrogens completely disappeared from the reaction on the product side. I wasn’t told to, but do I need to add them in and balance the equation? If I were to add the Hydrogens to The products, I would have 2 moles of H2, right? Because if I did it that would balance the equation and make the number of moles the same, justifying the answer.
If that is not the case, then I am confused as to why neither would be favored when there are 3 moles of reactant and only one mole of product.

[Shanna Yu 1C]

Hi!

The thing you pointed out in part D is actually a typo; the H2 should be on the right side, alongside the D2. Your proposed alternative explanation is correct in that having H2 on the other side would justify the given answer!

[Asia Yamada 2B]

That’s a typo! You can refer to the correct chemical equation here: https://lavelle.chem.ucla.edu/wp-conten ... rs_7Ed.pdf