A buffer solution is prepared by mixing 300 cm3 of 1.50 mol dm-3 ethanoic acid, CH3COOH\text{CH}_3\text{COOH}CH3COOH, with 500 cm3 of 1.20 mol dm-3 sodium ethanoate, CH3COONa\text{CH}_3\text{COONa}CH3COONa. Given that Ka K_a\,Ka for CH3COOH=1.75×10−5 mol dm−3\text{CH}_3\text{COOH} = 1.75 \times 10^{-5}\text{ mol dm}^{-3}CH3COOH=1.75×10−5 mol dm−3, what is the pH of the buffer solution?
4.63
4.76
4.88
5.01