What colour does litmus paper turn when dipped in lemon juice?
Litmus paper would turn red in lemon juice as it is acidic because of the citric acid content.
It would remain red, red litmus paper only reacts to blue in the presence of a base. Lemon juice is acidic and thus wouldn't turn the paper a color. If blue litmus paper was used in the lemon juice it would turn red. Consequently dipping blue litmus paper in a base won't change the color because it does not react with bases, only acids.
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?
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…