In the arrangement will be the potential difference between the terminals A and B after the battery is removed and the switch S is closed ?

Total charge stored in the system is Q =  10×3×2+43+2+4μC=20μCafter the battery is removed and S is closed, total charge   in the system between A and B, is Q1 = Q = 20µC∴VAB=Q'2+4volt=206volt=3.33volt