# Balancing molecular and net ionic equations for reactions

Source:'Chemistry: The Central Science 11th edition' by Brown. Ch.4, 4.53:
Question:

Write balanced molecular and net ionic equations for the reactions of:

1. chromium with hydrobromic acid;
2. tin with hydrochloric acid.

My attempts:

1. $\ce{ Cr(s) + 2HBr(aq) →CrBr2(aq)~ or~ CrBr3(aq)? + H2(g)}$

I got the left part of the reaction correct, but I can't figure out what charge chromium should have because it can have either $\ce{+2}$ charge or $\ce{+3}$ charge when it ionizes. The answer says that it should be $\ce{CrBr2}$, but why can't it be $\ce{CrBr3}$?

2. same thing for this option. Why can't $\ce{SnCl4}$ can be an answer?