Дано
m = 120 г
w(HCl) = 35% = 0.35
w(NaOH) = 20% = 0.2
Решение
m(HCl) = mw(HCl) = 120 * 0.35 = 42 г
n(HCl) = m(HCl) / M(HCl) = 42 / (1 + 35.5) = 1.15 моль
NaOH + HCl = NaCl + H2O
n(NaOH) = n(HCl) = 1.15 моль
m(NaOH) = n(NaOH)M(NaOH) = 1.15 * (23 + 16 + 1) = 46 г
m2 = m(NaOH) / w(NaOH) = 230 г
Ответ: 230 г