pippenyen wrote:如果是A,用觀察法...(恕刪) Yes, the answer is A, may I know the reason? How to use 觀察法? Thanks.
unl7911 wrote:Yes, the a...(恕刪) To my knowledge, B and D are alkaline and C is neutral. The pH value is changed from 7.3 to 7, which means the mixture (aqueous solution) is ACID. Therefore, HCl is the answer you have to choose.