Which hydroxide is formed when potassium reacts with water?

Which hydroxide is formed when potassium reacts with water?

• A. Lithium hydroxide
• B. Sodium hydroxide
• C. Potassium hydroxide
• D. Barium hydroxide

Answer: (C)

When an alkali metal like potassium reacts with water, the metal forms its own hydroxide and releases hydrogen gas. This happens because the metal donates electrons to water, and the resulting product combines with the hydroxide from water to give the metal hydroxide of the reacting element. For potassium, that product is potassium hydroxide (KOH). The reaction can be shown as 2K + 2H2O → 2KOH + H2, illustrating that the hydroxide formed matches the metal involved. The other hydroxides listed would come from reactions of lithium, sodium, or barium with water, not potassium, so they aren’t produced in this reaction.

When an alkali metal like potassium reacts with water, the metal forms its own hydroxide and releases hydrogen gas. This happens because the metal donates electrons to water, and the resulting product combines with the hydroxide from water to give the metal hydroxide of the reacting element. For potassium, that product is potassium hydroxide (KOH). The reaction can be shown as 2K + 2H2O → 2KOH + H2, illustrating that the hydroxide formed matches the metal involved. The other hydroxides listed would come from reactions of lithium, sodium, or barium with water, not potassium, so they aren’t produced in this reaction.