What gas is produce if a lime juice added with zinc powder?

The reaction between lime juice (which contains citric acid) and zinc powder produces hydrogen gas. The chemical equation for this reaction is:

2C6H8O7 + 2Zn → 2C6H5O7Zn + H2

In this reaction, the citric acid donates protons (H+) to the zinc atoms, which are oxidized to form zinc ions (Zn2+). The electrons released by the zinc atoms are then transferred to the hydrogen ions, which are reduced to form hydrogen gas (H2).

The hydrogen gas produced in this reaction is flammable and can be used as a fuel. It is also a reducing agent, and can be used to reduce other metal ions to their elemental form.