It was 80% u do the moles found in part (i) - the moles found in the titration with HCl, divide that by 2, and multiply by molecular mass of CO2, then divide that by original amount.
i Thought it was once the overall concentrations have increased, the ratio needs to be re-achieved, so the H and N increase slightly, and the ammonia decreases slightly, because the overall concentration was increased at a ratio of 1:1