Which of the following substances contains nitrous oxide?

• A. Baking soda (NaHCO3)
• B. Table salt (NaCl)
• C. Vinegar (acetic acid)
• D. Laughing gas used in dental procedures

Answer: (D)

Verified step by step guidance

1. Understand that nitrous oxide is a chemical compound with the formula \(\mathrm{N_2O}\), commonly known as laughing gas.
2. Review the chemical formulas of the given substances: Baking soda is \(\mathrm{NaHCO_3}\), Table salt is \(\mathrm{NaCl}\), and Vinegar is acetic acid with formula \(\mathrm{CH_3COOH}\).
3. Compare these formulas to the formula of nitrous oxide (\(\mathrm{N_2O}\)) to see if any match or contain the \(\mathrm{N_2O}\) unit.
4. Recognize that none of the given substances contain the \(\mathrm{N_2O}\) molecule; instead, nitrous oxide is a separate compound used as laughing gas in dental procedures.
5. Conclude that the substance containing nitrous oxide is not among the listed options but is specifically the compound known as laughing gas, \(\mathrm{N_2O}\).