M,C6H5OH= 94g/mol
niu=m/M= 94/94 mol=1mol FENOL
c= mdx100/ms---> md= 20x400/100g= 80g
niu,NaOH= m/M= 80/40mol= 2mol NaOH
1mol................1mol
C6H5OH + NaOH---> C6H5ONa + H2O
rezulta ca ramane in exces, 1mol NaOH
1mol..........1mol
NaOH + HCl------> NaCl + H2O
este necesar 1mol HCl
la HCl concentratia normala= concentratia molara
c= niu/V---> V= 1/2 L= 0,5L