Question

Solution A gives pink color when a drop of phenolphthalein indicator is added to it. Solution B gives red color when a drop of methyl orange is added to it. What type of solutions are A and B and which of these will have a higher pH value?

Answer 1

1. Indicators are substances which are used to identify the acidic and basic characteristics of different solutions.
2. The common indicators used are Litmus paper, Phenolphthalein, and methyl orange.
3. Phenolphthalein is colourless in neutral or acidic solution and turns to pink colour in basic solution.
4. Methyl orange is an orange colour dye which remains orange in a neutral solution, while in an acidic solution it changes to red and yellow in the basic solution.
5. Here, solution A gives pink color when a drop of phenolphthalein indicator is added to it implying that the solution is basic in nature.
6. And, solution B gives red color when a drop of methyl orange is added to it implying that the solution is acidic in nature.

Now as we know that;

1. The pH value ranges from 0 to 14.
2. Acidic solutions have a pH value less than 7, basic solutions have a pH value greater than 7, and neutral solutions have a pH value equal to 7.
3. Here, as solution A is basic it will have a pH greater than 7, and solution B which is acidic in nature has a pH value less than 7,
4. Therefore, solution A will have a pH value greater than solution B.

Hence, Solution A is the basic solution, solution B is the acidic solution, and solution A will have a pH value greater than solution B.