Does hydrogen builds all the acids??

Wow that a lot of text for my tiny so i no wanna answer

It will appear as o2(g) as a reactant 

Qand k are only the same when the forward rate of the reaction has reached zero.

The population of unionid mussels decreased after zebra mussels were introduced. zebra mussels competed with the unionid mussels for food. the zebra mussels were able to displace the unionid mussels, allowing the zebra mussel population to increase  over the years. the unionid mussel population decreased because  of lack of food.