Answer
$pH = 7$
Work Step by Step
1. Find the number of moles of HBr and NaOH:
HBr:
$n(moles) = V(L) * C = 0.02 * 0.2 = 0.004 moles$
NaOH:
$n(moles) = V(L) * C = 0.02 * 0.2 = 0.004 moles$
2. Since HBr is a strong acid, and NaOH is a strong base:
$n(HBr) = n(H^+) = 0.004 moles$
$n(NaOH) = n(OH^-) = 0.004 moles$
3. Find the excess of H+:
*The H+ reacted with OH- in a proportion of 1 to 1.
$0.004 - 0.004 = 0 (H^+)$
Since there are no excess of OH- or H+, the pH is neutral(7).
