Question

When 25ml of 0.10 mol/l HBr is titrated with 0.10 mol/l NaOH, what is the pH at the equivalence point?

Answer 1

You will have the salt of a strong base and a strong acid; therefore, the pH will be 7.0

Answer 2

Whenever you titrate a strong acid with a strong base, the pH at the equivalence point is 7.00.
Whenever you titrate a strong acid with a weak base, the pH at the equivalence point is less than 7.00.
Whenever you titrate a weak acid with a strong base, the pH at the equivalence point is greater than 7.00.

Now, you will say: why?

HBr(aq) + NaOH(aq) -----> NaBr(aq) + H2O(l)
0.10 M ...... 0.10 M

Strong acid ionizes completely
HBr(aq) -------> H+(aq) + Br-(aq)
0.10 M ............. 0.10 M

Strong base dissociates completely:
NaOH(aq) -------> Na+(aq) + OH-(aq)
0.10 M .................................... 0.10 M

At the equivalence point:
Mole H+ = Mole OH-

After neutralization the solution contains Na+ and Br- ions. Since these ions cannot hydrolize ( react with water to produce H+ or OH-), the solution becomes completely neutral.