Which of the following is used by dentists as a substitute for anaesthetic? A. oxygen B. nitrogen C. nitrous oxide D. chlorine

oxygen
nitrogen
nitrous oxide
chlorine

The correct answer is C. nitrous oxide. Nitrous oxide, also known as laughing gas, is a gas that is used as an anesthetic. It is inhaled and can cause a feeling of euphoria and relaxation. It is often used in dentistry to numb the pain of dental procedures.

Oxygen is a gas that is essential for life. It is used by the body to produce energy. Nitrogen is a gas that makes up about 78% of the Earth’s atmosphere. It is not used as an anesthetic. Chlorine is a gas that is used to disinfect water and to make bleach. It is not used as an anesthetic.

Nitrous oxide is a safe and effective anesthetic. It is used by millions of people each year. It is important to note that nitrous oxide is not a substitute for general anesthesia. General anesthesia is a much more powerful anesthetic that is used for major surgery.