I discovered by accident that, if I combined 1/4 teaspoon of baking soda and 1/4 teaspoon of vitamin C (ascorbic acid powder) in about 3 or 4 ounces of chlorinated water, that the water will turn yellow just like it does when water testing drops are used.* The big difference is that it takes the baking soda and vitamin C longer to show the reaction. So, I decided to try a little experiment.
The information that comes with Brita water filters claims that the filters take the taste and odor of chlorine out of the water and that they reduce the amount of chlorine in the water. The chart that comes with it shows by what amount the chlorine is supposed to be reduced.
Does it work? To find out, I took one glass and put tap water in it, another and put Brita filtered water in it, and another and put bottled spring water in it. The bottled spring water came from Walgreens and is the "Nice" brand. In each glass I put about 3 ounces of water and mixed in about 1/4 teaspoon of baking soda and 1/4 teaspoon of ascorbic acid powder. Then I set them aside for about 24 hours.
Now for the results. Here they are, right to left! On the right is the tap water - quite yellow, almost an orangish pink. (It looks pinkish when it is held up to the light.) In the middle is the Brita water - slightly yellow. On the left is the bottled spring water - still perfectly clear after 24 hours. You can try this at home with your own water. You only need clear glasses or clear containers, a little water, baking soda, ascorbic acid powder, and a little patience. It would be interesting to see what you come up with.
*Please note. I'm not suggesting that this is a chlorine detection technique. I simply noticed that this reaction happens in chlorinated water and thought it was interesting. It would also be fun to find out if other people came up with the same results.