ALEKS Placement Chemistry Practice Exam

The ion represented by the formula OH(-) is known as hydroxide. Hydroxide consists of one oxygen atom covalently bonded to one hydrogen atom, and it carries a negative charge, which signifies that it can donate a proton in chemical reactions. This characteristic allows hydroxide ions to play a crucial role in basic (alkaline) solutions, where they can react with acids to form water and a salt.

Understanding this concept is important because hydroxide ions are often involved in acid-base chemistry, where the balance between hydroxide and hydrogen ions (H+) determines the acidity or basicity of a solution. Additionally, in various chemical processes, hydroxide can act as a powerful nucleophile, participating in many organic reactions.

The other options represent different types of ions that do not have the same composition or charge as hydroxide. Oxide refers to O2- ions, sulfide refers to S2- ions, and phosphate corresponds to PO4^3- ions, which all have distinct characteristics and roles in chemistry separate from hydroxide.