Which of the following statements is true about metal oxides and hydroxides?

Metal oxides and hydroxides are classified as bases because they can neutralize acids, forming water and a salt in the process. This characteristic is fundamental to the definitions of acids and bases in chemistry, particularly in the context of the Brønsted-Lowry theory, which identifies acids as proton donors and bases as proton acceptors. Metal oxides, which are compounds of metals combined with oxygen, typically exhibit basic properties, especially when they react with acidic substances.

In the case of metal hydroxides, they are formed when metals react with water or when they combine with hydroxide ions (OH-). These compounds, like sodium hydroxide (NaOH) and potassium hydroxide (KOH), further demonstrate their basic nature by readily dissolving in water to produce hydroxide ions, which increase the pH of the solution.

This understanding is supported by common laboratory observations, where both metal oxides and hydroxides can neutralize acids, thereby confirming their classification as bases.