(b) (5 marks) HEPES has . Write down the chemical reaction relevant to the buffering capacity of HEPES.

(a) (5 marks). From elemental analysis, it is found that MSG contains the following mass distribution: carbon (35.00%), hydrogen (4.69%), nitrogen (8.16%), oxygen (38.57%), sodium (13.52%). Find the empirical formula of MSG [Molar mass information (g/mol): carbon 12.01, hydrogen 1.01, nitrogen 14.01, oxygen 16.00, sodium 23.00]