*IJMB CHEMISTRY, ABU* *(1c)* Reason for Methyl Orange over Phenolphthalein Because the titration is between a strong acid (H₂SO₄) and a weak base (Na₂CO₃), methyl orange is appropriate as it changes color in the acidic pH range (3.1–4.4), while phenolphthalein changes in the basic range and would not give a sharp endpoint.