Turmeric turns reddish-brown and red litmus turns blue in a solution. Which ion is likely to be in excess?
Answer and explanation
Correct answer: Hydroxide ion
Both observations indicate a basic medium. Turmeric changes to a reddish-brown colour in the presence of a base, and red litmus turns blue when the solution is basic. In the Arrhenius description, basicity in aqueous solution is associated with an excess of hydroxide ions, OH⁻, relative to hydrogen ions. Chloride and sulphate ions may be present in salts but do not alone explain these indicator changes. Therefore option B is correct.
Frequently asked questions
What is the correct answer to this question?
Hydroxide ion
Why is this the correct answer?
Both observations indicate a basic medium. Turmeric changes to a reddish-brown colour in the presence of a base, and red litmus turns blue when the solution is basic. In the Arrhenius description, basicity in aqueous solution is associated with an excess of hydroxide ions, OH⁻, relative to hydrogen ions. Chloride and sulphate ions may be present in salts but do not alone explain these indicator changes. Therefore option B is correct.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Acids, Bases, and Salts.
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