What is the purpose of performing the experiment in a well-ventilated room?

• A. To speed up the reaction.
• B. To prevent the burning of the substance.
• C. To ensure precise weighing.
• D. To keep the heating uniform.

Answer: (B)

Ventilation is about safety when vapors or gases are produced during an experiment. A well-ventilated room carries away and dilutes any fumes, reducing the concentration of potentially harmful or flammable vapors. This lowers the risk that those vapors could ignite and cause burning or a fire. The other aspects—reaction speed, precise weighing, or heating uniformity—aren’t governed by ventilation in the same way, so ventilation’s main role here is to prevent ignition hazards by removing vapors.