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1. solution student was handed three solutions, labeled 1, 2, and 3. She was tol

ID: 707276 • Letter: 1

Question

1. solution student was handed three solutions, labeled 1, 2, and 3. She was told that one conained o.IM HNO3, another contained 0.1M KOH, and the third contained a sol eWhen she mixed equal amount of two of the solution I mixed with 2 gave a blue solutio s she got the following results: n. T mixed with 3 gave a colorless solution. 2 mixed with 3 gave a red solution. Identily the solutions. Solution 1 was Solution 2 was Solution 3 was She then mixed equal amounts of all three solutions. What color did she get? Explain. Ceramic Plate used for sample testing.

Explanation / Answer

Thymol blue (thymolsulphonephthalein) used as a pH indicator.It transitions from red to yellow at pH 1.2–2.8 and from yellow to blue at pH 8.0–9.6.

it will give following colour

RED - pH below 1.2

YELLOW - pH between 2.8 and 8

BLUE - pH above 9.6

When Solution 1 is mixed with solution 2 blue colour is formed that shows that it is reaction between an alkali and thymol blue indicator hence solutions involved are KOH and thymol blue

When solution 2 is mixed with solution 3 red colour is formed indicating acid and thymol blue reaction. Hence solution involved are HNO3 and thymole blue.

From above two observations thymol blue is commen in both and hence it is solution 2

thus

solution 1 - KOH

solution 2 - thymol blue

solution 3 - HNO3

When Solution 1 and 3 ( ie, KOH and HNO3 respectively ) nutrelization reaction occures and KNO3 and H2O are formed which is colourless.

When all three solutions are mixed in equal quantities neutralization of KOH and HNO3 takes places , since the one reactent is strong acid and other a strong base salt formed will be neutral and hen thymol blue will indicate yellow colour