An indicator solution was obtained by boiling a flower in water - HSC - SSCE Chemistry - Question 11 - 2023 - Paper 1
Question 11
An indicator solution was obtained by boiling a flower in water.
Flower water indicator chart
Colour Red Purple Blue Blue-green Green-yellow
pH ... show full transcript
Worked Solution & Example Answer:An indicator solution was obtained by boiling a flower in water - HSC - SSCE Chemistry - Question 11 - 2023 - Paper 1
Step 1
H₂SO₄ (1 × 10⁻⁵ mol L⁻¹)
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Answer
To identify the colour of the H₂SO₄ solution, we note that it is a strong acid. The pH of 1 × 10⁻⁵ mol L⁻¹ H₂SO₄ is approximately 4, which corresponds to the colour Blue-green in the indicator chart.
Step 2
NaOH (5 × 10⁻⁵ mol L⁻¹)
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Answer
NaOH is a strong base. The pH of 5 × 10⁻⁵ mol L⁻¹ NaOH is approximately 10, which corresponds to the colour Green-yellow in the indicator chart.
Step 3
Correct identification of colours
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Answer
Based on the above observations, the colour identification of each solution is:
H₂SO₄ corresponds to Blue-green
NaOH corresponds to Green-yellow
Thus, the correct choice from the options provided is C: Purple - Blue-green.
