PTHH: Ba(OH)2 + 2HCl -> BaCl2 + 2H2O
NaOH + HCl -> NaCl + H2O
Ta có:
nHCl = 0,5.1 = 0,5 mol
mNaOH = 50.20% = 10 gam
=> nNaOH = 10/40 = 0,25 mol
=> nHCl = 2nBa(OH)2 + nNaOH
=> nBa(OH)2 = (0,5−0,25)/2 = 0,125 mol
=> a = CM Ba(OH)2 = 0,125/0,2 = 0,625M