When drop of lemon juice are put on blue litmus it turn red what will happen if you put some drops of soap solution on the same position on litmus paper?

Answer 1

The litmus papers are used for checking the acidic and basic nature of any substance. That's why drop of lemon juice, which is by nature acidic, turns blue litmus into red(as the property of acidic solution is to change the color of blue litmus to red). So soap solution which is by nature basic will turn red litmus into blue (as the property of basic solution is to change the color of red litmus to blue).

Answer 2

The soap solution, being basic in nature, will likely cause the litmus paper to turn back to blue or purple. This is because soap solutions typically have a high pH, which indicates alkalinity and would counteract the acidic effect of the lemon juice on the litmus paper.