Final answer:
All listed compounds are bases except for 2. HNO₃, which is a strong acid. KOH, LiOH, and Mg(OH)₂ contain the hydroxide ion and are bases, while HNO₃ increases hydrogen ion concentration in water.
Step-by-step explanation:
All of the following are bases except 2. HNO₃ (nitric acid), which is a strong acid. A base typically contains the hydroxide ion (OH⁻), and it will increase the OH⁻ concentration in solution when dissolved in water. The compounds KOH (potassium hydroxide), LiOH (lithium hydroxide), and Mg(OH)₂ (magnesium hydroxide) all contain the hydroxide ion and are considered bases. However, HNO₃ is not a base because it is an acid that increases the concentration of hydrogen ions (H⁺) in an aqueous solution.
Examples of strong bases include NaOH (sodium hydroxide) and KOH, while HNO₃ is listed among strong acids like HCl and H₂SO₄ (sulfuric acid). Strong bases are often hydroxides of alkali and heavy alkaline earth metals, which dissociate completely in water to produce hydroxide ions.
Formulas for bases mentioned are:
- Nickel (II) hydroxide: Ni(OH)₂
- Aluminum hydroxide: Al(OH)₃
- Silver hydroxide: AgOH