we hear the terms acid and base all the time and could probably name some common household acids and bases but what do these words mean on the molecular level if we go by the Bron stead Lowry model of acids and bases an acid is something that donates a hydrogen ion and a base is something that accepts a hydrogen ion and an acid base reaction is one in which a hydrogen ion is transferred from one molecule to another an H+ ion is also referred to as a proton because if a hydrogen atom which is one proton and one electron becomes a one plus ion it will lose its electron and therefore become simply a proton when a strong acid dissociates in aquous solution every acid molecule will transfer a proton onto a water molecule forming a hyd dronium ion or h3o+ here is an acidbase reaction involving hydrochloric acid which is a strong acid in every acidbase reaction there is an acid in this case hydrochloric acid and a base in this case water the products will be the conjugate base of the acid in this case the chloride ion and the conjugate acid of the base which here is hydronium this image illustrates the addition of HCL to water to produce the chloride ions and hydronium ions notice that every molecule of acid transfers a proton to a water molecule here are some common strong acids there are also weak acids these transfer protons to water molecules too but they do not react completely they will establish some kind of equilibrium between the acid and the conjugate base a strong base is something that will steal a proton from a water molecule to produce a hydroxide ion some strong bases are comprised of hydroxide ions themselves weak bases just like weak acids only partially react we should note that water can be referred to as amphoteric this means it can act as either an acid or a base we saw how water acts as a base in the presence of an acid becoming hydronium and in the presence of a base water can act as an acid becoming hydroxide if a strong acid and base react with one another hydroxide ions and hydrogen ions will combine to form water molecules and the remaining ions will stay in solution this is called a neutralization reaction because the acid and base rea react to form water a neutral compound let's see if we can predict the products in this acid base reaction and label all the components hypochlorous acid must be the acid and water must be the base so we will get the conjugate base the hypochlorite ion and the conjugate acid hydronium and now we know what acids and bases are