Predict the stronger acid in each pair: (a) HCl or HF; (b) H3PO4H3PO4 or H3AsO4j (c)HBrO3 or HBrO2; (d)H2C2O4 or HC2O4−; (e) benzoic acid (C6H5COOH) or phenol (C6H5OH).