Answer:
13.672
Step-by-step explanation:
2 moles of OH in Ba(OH)₂
0.235 M × 2 mol OH = 0.47 M OH
pOH = -log[OH-] ; pOH = -log[0.47 M OH] ; 0.328 = pOH (consider significant figures)
14 - pOH = pH because pH + pOH = 14
14 - 0.328 = 13.672 [there are three decimal places after the OH concentration, so there should be in the answer as well - 13.672]