The “Homework Solutions” cabinet contains a solution labeled "Unknown Acid," which is a weak mono-protic acid with an unknown Ka and with an unknown concentration. Your job is to determine the concentration and Ka to two significant figures. Please report your results and explain your procedure.

I do not know the answer ,sorry

One mole of gas occupies 22.4 liters, 5*1/22.4=0.22 moles of carbon dioxide ration of oxygen to carbon dioxide is 1:2 so we divide 0.22 by 2 we get 0.11 moles of oxygen 1 mole occupies 22.4 litres, what if 0.11 moles of oxygen were used what volume would it occupy. so 0.11*22.4/1=2.5L