The results for the litmus tests are:
Tube 1. The solution is an alkali which turns blue when red litmus is added to it and remains blue when blue litmus is added to it.
Tube 2. The solution is an acid which remains red when red litmus is added to it and turns blue when red litmus is added to it.
Tube 3. The solution is water which remains red when red litmus is added to it and remains blue when blue litmus is added to it.