InterviewSolution
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InterviewSolution
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(a) Define a universal indicated . Mention its one use. (b) Solution A gives pink colour when a drop of phenolphthalein indicator is added to it. Solution B gives red colour when a drop of methyl orange is added to it. What type of solutions are A and B which one of the solutions A and B will have a higher pH value ? (c) Name one salt whose solutions has pH more than 7 and one salt whose solution has pH less than 7. |
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Answer» (a) Universal indicator is a mixture of many different indicators which gives different colours at different pH values of the entire pH scale. It shows different colours at different concentrations of hydrogen ions in a solution. (b) Solution A gives pink colour when a drop of phenolphthalein indicator is added, therefore A is a base. Solution B gives red colour when a drop of methyl orange is added to it, therefore B is an acid. Hence, solution A will have less concentration of hydrogen ion than B. Thus, A will have pH more than 7 because pH value of : -an acid solution `lt 7` , -a base solution `gt 7` , and - a neutral solution =7 (c) - The salts of strong acids and weak bases give acidic solution have pH less than 7. Example, `NH_(4)Cl`, Ammonium Chloride will have pH less than 7. -The salts of a weak , acids and strong bases give basic solution having pH more than 7. Examples, `Na_(2)CO_(3)`, Sodium Carbonate will have pH more than 7. |
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