題組內容

2. Na2CO3 is usually used as primary standard for standardize the concentration of HCl solution. There will be two equivalent points encountered during the titration process. ( for H2CO3, Ka1= 4.3 X 10-7, Ka2 = 4.7 X 10 -11 )

(B) Which of the following indicators is suitable for detecting equivalent point two? And give your reason. (4 分)