Answer
$pH = 2.886$
$pOH = 11.114$
Work Step by Step
1. Since $HNO_3$ is a strong acid: $[H_3O^+] = [HNO_3] = 0.0013M$
2. Calculate the pH value:
$pH = -log[H_3O^+]$
$pH = -log( 1.3 \times 10^{- 3})$
$pH = 2.886$
3. Use the pH value to calculate the pOH.
$pOH + pH = 14$
$pOH = 14 - pH = 14 - 2.886$
$pOH = 11.114$
