Question

According to the following reaction, how many moles of hydrobromic acid are necessary to form 0.723 moles bromine?

2HBr(aq) → H₂(g) + Br₂(l)
How many mol of hydrobromic acid?

Answer 1

To answer this question you need to use stoichiometry

We have the number of moles for bromine, we can use that, and the equation is balanced so we can move on

If you look at the reaction, how many moles of HBr are there per 1 Br2? There’s 2/1 or just 2 HBr per 1 Br2. Multiply that with 0.732
2 x 0.732 = 1.464 mol
Hope this helps