Question

What happens when lemon juice is added to zinc and produced a burning match stick

Answer 1

when lemon juice is added to zinc,zinc citrate is formed and hydrogen gas is evolved as lemon juice contain citric acid.
when a burning matchstick is produced to it,it will burn with a pop sound.

Answer 2

When lemon juice is added to zinc and a burning match stick is brought closer to it the following reactions take place:

a.   Zinc reacts with the citric acid of lemon to form Zinc Citrate and Hydrogen Gas.

b.   The released Hydrogen gas on coming in contact with fire from the match stick burns with a characteristic pop sound.

This particular experiment is used as an initial test for presence of Hydrogen gas.