Answer to Question #37170 in Other Chemistry for edward
The ammonia is added to couple the silver cations into a complex and thus avoid side reactions such as precipitation of silver chloride. Therefore it is used to increase the measurement accuracy.
Addition of HNO3 cannot restrain the ammonia with the sufficient efficiency. Binding the ammonia to the silver cations is more preferable compared to the ammonia interaction with protons. However nitric acid can oxidize sulfides which you are going to determine through titration.
thank you for your reply
but i had my solution acidify by HNO3. BUT I CAN NOT EARN TWO INFLECTION POINT?
Dear Tone! In presence of amine you cannot determine the amount of chloride. This is due to higher stability of silver-amine complexes compared to silver chloride. Therefore your inflection point occurs at the end of reaction of silver-amine complex with H2S. To obtain inflection point for chloride, you should continue titration in absence of amine.
I WANT DETERMINE H2S (80 PPM)& CHLORIDE(6 PPM) IN AMINE WITH POTENTIOMETRY WITH SILVER ELECTRODE BUT I CAN NOT DETERMINE IT I GAIN ONLY ONE INFLECTION POINT DO YOU KNOW?