Which gas is produced by a photocopier machine?

Photocopier machines are widely used in offices and schools for duplicating documents. During the operation of photocopiers, especially older models using electrical corona wires, a small amount of ozone (O₃) gas is produced.

Ozone is formed when oxygen molecules (O₂) in the air are split into individual oxygen atoms by high-voltage electrical discharge. These atoms can then combine with O₂ to form O₃. This reaction can be represented as:

3O2→electrical discharge2O33O_2 \xrightarrow{\text{electrical discharge}} 2O_33O2electrical discharge2O3

Although ozone is beneficial in the upper atmosphere where it forms the ozone layer protecting Earth from ultraviolet (UV) radiation, exposure to ozone at ground level can be harmful. Breathing ozone can irritate the lungs, eyes, and respiratory tract, and can cause headaches or coughing in sensitive individuals. Therefore, proper ventilation is important when operating photocopiers for extended periods.

Other gases like carbon dioxide (CO₂) or sulfur dioxide (SO₂) are not typically produced during photocopying. CO₂ is a byproduct of combustion or respiration, and SO₂ comes from burning fossil fuels containing sulfur.

Modern photocopiers are designed to minimize ozone emissions by using ozone filters or alternative technology that avoids corona wires. Nevertheless, understanding that O₃ is the gas associated with traditional photocopier operation is an important chemistry fact for both environmental safety and office hygiene.

In summary, the correct answer is Ozone (Option A). Photocopiers generate a small amount of O₃ due to electrical discharge of oxygen molecules, making this a key chemical concept for everyday science and chemistry education.