amount of hydroxide ions produced
The strength of a base depends on how many hydroxide ions it produces when it dissolves in water. A stronger base produces more hydroxide ions than a weaker base. For example, sodium hydroxide NaOH , a base in drain cleaner, is a strong base because all of it breaks down into ions when it dissolves in water. Calcium carbonate CaCO 3 , a base in antacids, is a weak base because only a small percentage of it breaks down into ions in water.