Question

16)La 188g de fenol se adauga 400 g se solutie naoh 40%.Volumul solutiei de hcl,0,5M,care trebuie adaugat pt ca solutia finala sa fie neutra este: c)4Litrii

Answer 1

md=c*ms/100=40*400/100=160g NaOH
facem reactia si vedem ce cantitate reactioneaza)
94g...............40g
C6H5-OH + NaOH -> C6H5-ONa + H2O
188g.............x=?
x=188*40/94=80g NaOH
160-80=80g NaOH nereactionate
40g........1mol
NaOH + HCl -> NaCl + H2O
80g........y=?
y=80*1/40=2moli
Cm=n/Vs => Vs=n/Cm=2/0,5=4L