When zinc is added to an unknown solution, a gas is released and it gives a pop sound near a burning splint. What could be the nature of the solution?
Answer and explanation
Correct answer: Acidic solution
The governing concept is the reaction of a sufficiently reactive metal with an acid. Zinc can displace hydrogen from many dilute acids, forming a salt and hydrogen gas; for example, Zn + 2HCl → ZnCl₂ + H₂. Hydrogen burns with a characteristic pop when tested near a flame or burning splint. Therefore the unknown solution could be acidic. Neutral water, salt solution, and sugar solution do not normally produce this test with zinc under these conditions, so B is correct.
Frequently asked questions
What is the correct answer to this question?
Acidic solution
Why is this the correct answer?
The governing concept is the reaction of a sufficiently reactive metal with an acid. Zinc can displace hydrogen from many dilute acids, forming a salt and hydrogen gas; for example, Zn + 2HCl → ZnCl₂ + H₂. Hydrogen burns with a characteristic pop when tested near a flame or burning splint. Therefore the unknown solution could be acidic. Neutral water, salt solution, and sugar solution do not normally produce this test with zinc under these conditions, so 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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