Chris observes that a drop of an unknown solution on red litmus paper causes no colour change. Chris correctly concludes the solution is either neutral or acidic, but cannot be sure which. Explain. What further test(s) could Chris perform to distinguish?
2 Answers
He is not sure because acids turn litmus paper red anyway. What you need to do is use blue litmus paper. If it changer to red, then its acidic, otherwise it would have changed nothing both times and would be neutral.
He must use another indicator besides red litmus.
Explanation:
Litmus is an acid base indicator. Litmus is green in a neutral solution. Litmus turns red in an acid. Litmus turns blue in a base.
If litmus is already red a neutral solution will not change the color of the litmus paper.
If litmus is already red a acidic solution will not change the color of the litmus paper.
Blue litmus paper will stay blue in a basic solution
Blue litmus paper will stay blue in a neutral solution.
Blue litmus paper will turn red in an acidic solution.
There are other indicators that will change color in an acidic solution that can be used.
