Oil
None, no gas is given off.
Ammonia gas (NH3) is given off when ammonia solution is heated.
hydrogen eg:Na+HCl------>NaCl+H2
Hydrogen gas is given off when magnesium reacts with sulfuric acid.
Carbon Dioxide is given off. (CO2)
Hydrogen gas.
Oxygen gas
Hydrogen gas is always given off when an acid solution is electrolyzed.
Dirty or faulty needle and seat in carburetor.
When you place a lighted splint into, say, a test tube, where you suspect hydrogen gas is being given off, a 'pop' sound indicates the presence of the gas.
Oxygen is given of
Turning off the main knob of the cylinder while the gas is not in use prevents any leaks or accidental release of gas, ensuring safety and conservation of gas supply. It also reduces the risk of fire hazards and gas wastage.