H because it is acidic
There are a total of 3 ions in Ca(OH)2. This includes one calcium ion (Ca2+) and two hydroxide ions (OH-).
A substance that produces OH- ions when added to water is a base. Bases are substances that increase the concentration of hydroxide ions in a solution. Some common examples of bases include sodium hydroxide (NaOH) and potassium hydroxide (KOH).
Milk of magnesia is a solution of magnesium hydroxide (a white powder) in water. It is a base because when the powder is introduced into water, it partially dissociates (breaks up) into magnesium (Mg2+) and hydroxide (OH-) ions. Pure water contains an equal number of OH- ions and another ion called hydronium ions (H3O+). Because the milk of magnesia adds OH- ions to the water, there are now more OH- ions than H3O+ ions. This means you have a base. On the opposite end, if there are more H3O+ ions than OH- ions, which happens when you add vinegar or lemon juice to water, you have an acid. Hope that makes sense!
Generally OH- ions. But there are bases without OH- ions.
Acids add Hydrogen Ions (H+) and not OH ions
A substance containing many OH ions is a base. Bases are substances that can accept protons (H+ ions) and release hydroxide ions (OH- ions) in water, leading to an increase in the pH of the solution.
An arrhenius acid is, by definition, a solution with a higher concentration of H+ ion than OH-. So any arrhenius acid will fit this definition. Two common acids are Lemon juice and vinegar.
acid produces H+ ions base produces OH- ions
When Ba(OH)2 dissociates in water, it forms Ba2+ ions and 2 OH- ions. The Ba2+ ion carries a double positive charge and is a cation, while the OH- ions are hydroxide ions and carry a single negative charge as anions.
OH- and H+
A base produces OH- ions in water, while acids do not produce OH- ions. When a base is dissolved in water, it releases OH- ions, increasing the concentration of hydroxide ions and raising the pH of the solution.