Acid-Base Indicators
Chemistry ⇒ Acids, Bases, and Salts
Acid-Base Indicators starts at 7 and continues till grade 12.
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See sample questions for grade 11
A solution turns blue litmus red. Is the solution acidic or basic?
A student adds phenolphthalein to a solution and observes no color change. What can be inferred about the pH of the solution?
A student is given a colorless solution and adds methyl orange. The solution turns red. What does this indicate about the solution's pH?
Describe the color change of methyl orange in acidic and basic solutions.
Describe the difference between a single indicator and a mixed indicator.
Explain why indicators are important in acid-base titrations.
Explain why phenolphthalein is not suitable for titrating a strong acid with a weak base.
Explain why universal indicator shows a range of colors.
Name one natural acid-base indicator other than litmus.
What is the color of phenolphthalein in a basic solution?
A solution is tested with three indicators: litmus (turns blue), methyl orange (turns yellow), and phenolphthalein (turns pink). What can you infer about the approximate pH range of the solution?
A student is performing a titration of 0.1 M acetic acid (CH₃COOH) with 0.1 M sodium hydroxide (NaOH). The student uses methyl orange as the indicator and observes a color change at a pH of about 4. Why is methyl orange not a suitable indicator for this titration?
Describe the molecular mechanism by which acid-base indicators change color in response to pH changes.
Explain why the choice of indicator is crucial in the titration of a weak acid with a weak base, and suggest a suitable indicator for such a titration.
Explain why universal indicator is preferred over single indicators for measuring the approximate pH of an unknown solution.
