A substance composed of a metal plus hydroxide is called a metal hydroxide.

Here's a breakdown:

* Metal: A chemical element that is typically shiny, malleable, and a good conductor of heat and electricity.

* Hydroxide: A polyatomic ion with the formula OH⁻.

Examples of metal hydroxides:

* Sodium hydroxide (NaOH)

* Potassium hydroxide (KOH)

* Calcium hydroxide (Ca(OH)₂)

* Aluminum hydroxide (Al(OH)₃)

Metal hydroxides are often used in:

* Industrial applications: As strong bases in chemical reactions, manufacturing, and cleaning.

* Medicine: As antacids, laxatives, and ingredients in some topical medications.

* Environmental applications: For wastewater treatment and soil remediation.