Which indicator would be best for this titration?
| Indicator | Colour change range (pH) |
|----------------------|--------------------------|
| A - HSC - SSCE Chemistry - Question 5 - 2019 - Paper 1
Question 5
Which indicator would be best for this titration?
| Indicator | Colour change range (pH) |
|----------------------|--------------------------|
| A. Marti... show full transcript
Worked Solution & Example Answer:Which indicator would be best for this titration?
| Indicator | Colour change range (pH) |
|----------------------|--------------------------|
| A - HSC - SSCE Chemistry - Question 5 - 2019 - Paper 1
Step 1
Identify the appropriate pH range for the titration
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Answer
To determine the best indicator for the titration, it's essential to know the pH at the equivalence point of the reaction. The ideal indicator should change color at or near this pH.
Step 2
Analyze the pH ranges of the indicators
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Answer
From the table:
Martius yellow: 2.0 – 3.2
Magdala red: 3.0 – 4.0
Isopricmic acid: 4.0 – 5.6
Cresol red: 7.2 – 8.8
Based on this data, we need to choose an indicator that covers the expected equivalence point of the titration.
Step 3
Select the best indicator from the given options
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Answer
If the equivalence point is around pH 4 to 5.6, the most suitable choice is Isopricmic acid (C), which has the closest range. Therefore, the answer is C.
