To determine which substances are most likely acids, we need to identify the substances that typically exhibit acidic properties. Acids are generally characterized by the presence of hydrogen ions (H⁺) and usually have hydrogen at the beginning of their chemical formula.
Let's analyze each substance given in the list:
1. CH₄ (Methane):
- Methane is a simple hydrocarbon that consists of one carbon atom bonded to four hydrogen atoms. It is not an acid; rather, it is a neutral hydrocarbon and does not release hydrogen ions in solution.
2. HI (Hydroiodic Acid):
- This compound is commonly known as hydroiodic acid, and its formula indicates the presence of hydrogen (H) combined with iodine (I). When dissolved in water, it dissociates to release hydrogen ions (H⁺), classifying it as an acid.
3. NH₃ (Ammonia):
- Ammonia consists of one nitrogen atom bonded to three hydrogen atoms. While it contains hydrogen, it does not release hydrogen ions in solution. Instead, it typically acts as a base in aqueous solutions by accepting hydrogen ions.
4. HNO₃ (Nitric Acid):
- Nitric acid is a well-known strong acid. The formula shows hydrogen (H) bonded to a nitrate group (NO₃). When it dissolves in water, it dissociates to release hydrogen ions (H⁺).
5. NaCl (Sodium Chloride):
- Sodium chloride is a salt formed from the neutralization of an acid (hydrochloric acid) and a base (sodium hydroxide). In its aqueous form, it dissociates into sodium ions (Na⁺) and chloride ions (Cl⁻), neither of which are hydrogen ions.
Based on this analysis, the substances from the list that are most likely to be acids are:
- HI (Hydroiodic Acid)
- HNO₃ (Nitric Acid)
Hence, the substances that are most likely acids are:
- HI
- HNO₃.
