C-09-Q012mediumsingle_mcqWhich of the following is a weak acid?aHCl\mathrm{HCl}HClbH2SO4\mathrm{H_2SO_4}H2SO4cHNO3\mathrm{HNO_3}HNO3dCH3COOH\mathrm{CH_3COOH}CH3COOH