chemistry (litmus paper)
posted by Lou .
When using litmus paper I was wondering why do you first wet it? Second, I wanted to know is why is it not suppose to touch the solution? Third, how doo you test for solutions if it is not suppose to touch the solution.
I suppose you intended to write "supposed."
a. It isn't necessary to wet the paper first but some workers like to do that.
b. You don't touch the solution with the paper because you don't want to contaminate the sample.
c. It's ok for the solution to touch the paper but not ok to touch the paper to the solution. So you place a stirring rod into the solution, take the wet stirring rod out of the solution and touch the wet glass (usually glass) rod to the paper. That way you can test the acidity of the solution without contaminating it.