A few days ago I made an experiment. I diluted a few small chunks of bar soap with 20 ml of water. I then measured the ph of the solution which was around 10. I then added a tiny amount of citric acid. I immediately noticed that the solution stopped foaming. I measured the ph again and it was around 5.
I am interested what actually happened when I added the citric acid? Since the solution stopped foaming and there were no more bubbles even with continuous stirring was the final solution still soap? How does the ph of a solution affect its detergent abilities/properties?