Question

What observation can be made after zinc granules are added to a test tube containing dilute HCL

Answer 1

Brisk effervescence due to the release of hydrogen gas is observed.

Answer 2

Answer: Effervescence due to hydrogen

Explanation: $Zn+2HCl\rightarrow ZnCl_2+H_2$

This is a single displacement reaction in which more reactive element replaces the less reactive metal from its salt solution.

Zinc being more reactive than hydrogen, loses electrons easily and hence displaces hydrogen from hydrogen chloride to produce effervescence of hydrogen gas and zinc chloride.