Exercise 9 | Chemical Calculations for Solutions
A few small drops of water are left in a buret that is then used to titrate a base into an acid solution to determine the concentration of the acid.
Will this small amount of water have any effect on the determined value for the concentration of the acid? If so, how is it affected?
Yes, this small amount of water will cause an error.
When the endpoint of the neutralization is reached: number of moles of acid = number of moles of base
⇒ Macid x Vacid = Mbase x Vbase
Due to the water drops added to the volume of base, the base solution is slightly diluted
⇒ Mbase is lower than expected
This means that it will take more of the basic solution to neutralize the acid
⇒ the concentration of the acidic solution will appear higher concentration than it actually is.