Question

Titration Problem - Calculate the concentration of 20.0 mL of an H2SO4 solution that requires 27.7 mL of a 0.100 M NaOH solution?

Answer 1

`0.06925M`

Explanation:

`2NaOH+H_2SO_4`--->`Na_2SO_4+2H_2O`

First calculate the number of moles (or amount) of the known solution, which in this case is the NaOH solution.
The volume of NaOH is `27.7 mL`, or `0.0277L`.
The concentration of NaOH is `0.100M`, or in other words, `0.100` mol/L

Amount = concentration x volume

`0.0277Lxx0.100M=0.00277` `mol`

As you can see from the reaction equation, the amount of `H2_SO_4` is half the amount of `NaOH`, as there is `2NaOH` but only `1H_2SO_4`

Amount of `H_2SO_4=0.00277/2=0.001385` `mol`

Concentration = amount/volume

`0.001385` `mol`/`0.02L=0.06925M`