For theoretical purpose, the formation of gas is generally indicated by an upward arrow.
Experimentally, sometimes vapours are seen, if the gas is coloured.
At the positive electrode, oxygen gas was produced.
The gas produced when fuels are burned is carbon dioxide (CO2).
When aluminum reacts with sodium hydroxide, hydrogen gas is produced along with sodium aluminate as a byproduct.
A salt. The type of salt depends on the type of acid.
When iodine is heated, it sublimes directly from a solid to a purple gas. The gas produced is diatomic iodine molecules (I2).
You can see the release of this gas.
It is sign of chemical reaction because smell and heat is produced.
Chlorine gas is produced.
One sign that a reaction has taken place between a metal and an acid is the formation of bubbles of gas. This gas is often hydrogen gas, which is produced when the metal reacts with the acid. Additionally, the metal may appear to dissolve or disappear as it reacts with the acid.
Chlorine gas is produced.
oxygen
When a battery is charging, hydrogen gas is produced.
At the positive electrode, oxygen gas was produced.
Hydrogen gas is produced.
Hydrogen gas (H2) would be produced.
The gas produced when fuels are burned is carbon dioxide (CO2).
When a battery is being charged, hydrogen gas is produced.