Which amongst the following can be observed when zinc granules are added to dilute hydrochloric acid taken in a test tube?

When zinc granules are added to dilute hydrochloric acid in a test tube, the following observations can be made:

1. Reaction: Zinc reacts with hydrochloric acid to form zinc chloride and hydrogen gas. The chemical equation for this reaction is: Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g)

2. Effervescence: You will observe effervescence or bubbling in the test tube. This is due to the formation and release of hydrogen gas.

3. Heat: The reaction is exothermic, meaning it releases heat. Therefore, the test tube will become warm.

4. Dissolution: The zinc granules will gradually dissolve in the hydrochloric acid as they react to form zinc chloride, which is soluble in water.

5. Test for Hydrogen: If you bring a burning matchstick or candle near the mouth of the test tube, the hydrogen gas will burn with a 'pop' sound. This is a positive test for hydrogen gas.