 So when we're talking about acid and base solutions We need to be very clear about exactly what it is that we're talking about and if I take the second one of these first Concentration of an acid is about the ratio of Acid to water Now often when we're young we we have drinks to which we add water like cordials and And so therefore we use words like it tastes really strong when what we mean is really concentrated We need to add a little bit more water or this tastes really weak Which is our way of saying there's just too much water here. I can't taste much else as Chemists we need to realize that these sort of common uses of these words are actually incorrect And we need to realize that when we're describing the ratio of acid to water in any solution We're talking about its concentration So therefore we talk about a concentrated solution, which is high solute low solvent In our example there would be lots of acid molecules or ions to Low water or a dilute solution and the dilute solution is one in which we have low solute To high solvent So in other words lots more water in our dilute solution than there is in our concentrated solution So that's one way of describing acid and base solutions, but what about strength if strength isn't about the amount of water What is it about? Well, the strength of an acid is its degree It's actually a measure of its degree of ionization And if we were to talk about a base then it would likewise be its degree of ionization or Dissociation how readily the ions separate into water You can also talk about the relative ease with which either water molecules will Take that proton that acids can donate or pull apart separate the ionic bonds between The ions in a base So the strength of an acid is a measure of the degree of ionization So for example, if we look at something very simple such as hydrochloric acid when this is in solution it's going to form hydrogen ions and chloride ions if there are lots of These and few of these then we would say this is a strong Acid and in fact that is the case for hydrochloric acid however, if we had an acid where there was lots of the HCl molecule for example or the acid molecule and few of the ions then we would call this a weak acid So the terms strong and weak are associated with the degree of ionization For hydrochloric acid the first one is the correct one It's a strong acid because it fully ionizes in water all of the HCl molecules are actually ionized to form H plus or hydronium ions H3O plus with water and chloride ions So we can have a strong Concentrated solution or a strong dilute solution. We can also have a weak Concentrated solution and a weak dilute solution. So these these terms are not interchangeable They have specific meanings and descriptors when we use them about acid and base solutions