What is the concentration of the solution?
What is in the flask?
The acid is HCl and an indicator such as phenolphthalein
What is in the flask? H+ The H+ ions cause the indicator to be colourless.
H+ OH- Titration begins
HCl H+ NaOH Titration begins + water NaCl +
H+ OH- Titration begins + water
H+ OH- Titration continues + water
H+ OH- Titration continues + water But there is enough H+ to keep the indicator colourless.
H+OH- Just when all the H+ is used up… + water The indicator changes colour.
H+OH- Just when all the H+ is used up… + water This is called the ENDPOINT. And no more OH- is added.
H+OH-+ water The moles of H+ is equal to the moles of OH- At the ENDPOINT…
At the End-Point … and if moles of base = moles of acid If Molarity = moles Volume then (Molarity acid) (Vol acid)=(Molarity base) (Vol base) then moles = (Molarity) (Volume)
known volume At endpoint…
(Molarity acid) (Vol acid)=(Molarity base) (Vol base)
(Molarity acid) (Vol acid)=(Molarity base) (Vol base)