What happens when dilute hydrochloric acid is added to zinc pieces taken in a test tube:
The correct option is D.
Small bubbles of hydrogen gas appear on the surface of zinc pieces.
Explanation:
Zn+2HCl(dil.)→ZnCl2+H2Hydrogen gas↑
The above reaction is a single displacement reaction. Zinc displaces hydrogen from the acid and hydrogen gas comes out in the form of small bubbles.