M(NaOH * 4H2O) = 23 + 16 + 1 + 4 * 18 = 112 г/м
M(NaOH) = 40г/м
80г ------------ 112г
х(NaOH) ------------ 40г
х = 28.56г
NaOH + HCl = NaCl + H2O
n(NaOH) = 28.56 / 40 = 0.714
n(HCl) = n(NaOH) = 0.714
m(HCl) = 0.714 * 36.5 = 26.061
M(HCl) = 36.5
20% ----------- 26.061 г
100 % --------- х
х = 100 * 26.061 / 20 = 130.3 г