NaOH + HCl = NaCl + H2O
Cf. ec. react. chimice:
1 mol HCl.................... 1 mol NaOH
0,2 moli...........................x
x = 0,2 moli NaOH
M NaOH = A Na + A O+A H = 23 +16+1 = 40
1 mol NaOH = 40 gNaOH
n = m/M, mNaOH = 0,2 .40 = 8 g NaOH
c= (md/ms).100, deci ms=md.100/c; msNaOH = 8.100/20=40 g sol.NaOH 20%