Is it plausible that free chlorine could be formed in concentrated hydrochloric acid.
The background to this is that I have bought some 30% HCl to remove calcium carbonate scale from a reverse osmosis water purifier. The latest batch of HCl seems to have a very slight yellowish tint which I had not noticed on previous occasions. Having used some of this acid I find that the performance of the membrane seems to have deteriorated (these membranes are notably sensitive to hypochlorite).
Could some factor (perhaps exposure to direct sunlight) be responsible?
Is there a way that I could detect the presence of dissolved chlorine?
Can anyone suggest an alternative explanation?