Here it says complete and balance the following reaction. So here we have arsenic with three flooring, so we have a trihalet. Trihalids make oxy acids, 3 halogens make 3 oxygens. For oxyhalid it would be H₃.

Arsenics are group 5A, element O₃ and then we'd have our hydrogen halid, so that'd be H with the flooring balancing it out. This would be aqueous, Aqueous. We balance this out. We put a three here, We put A1 here. We already have a three here and A1 here, so now our equation is balanced.

So again, try halids 3 halogens. Create oxy acids with three oxygens.