Hey there,
I'm doing notes under the syllabus right now, and I don't think I've got any sufficient notes on the following dot point:
'describe the difference between a strong and a weak acid in terms of an equilibrium between the intact molecule and its ions'
If you could help me out, it'd be much appreciated.
Thanks
Hey!!
Basically, for that dot point I would have a few things up your sleeve.
Definitions of strong and weak acidsAlways start by defining things. A strong acid is, by definition, an acid that ionises completely in solution. A weak acid is just any acid that does NOT ionise completely in solution (and usually only ionises to a tiny extent, eg. 1-10%).
FormulasBut what do the above statements even mean? The easiest way to describe strong and weak acids in terms of equilibrium is to use equations. So, let's do that!
Let's start by looking at a strong acid. I always like to use HCl, because its the one used most often in the HSC.
We write the reaction of HCl and Water to show ionisation.
Now, we know that HCl is a strong acid, and so ionises completely. In terms of equilibrium, this means that the reaction lies
entirely to the right!Now, let's look at weak acids or weak bases. You can use whatever weak acid or base you want.
First, we write out the equation.
Now, we know that Ammonia is a weak base. Therefore, in terms of equilibrium, we can say that the reaction
lies largely to the left!That's really all you need to know in terms of acids/bases and equilibrium. Hope it helps!
Jake