Question

se titreaza v=5 ml dintr-o solutie de nh3 6.12%(d=0.973g/cm3) cu o solutie hcl 2n. sa se calculeze volumul de titrant consumat.

Answer 1

-  calculez masa celor 5 ml solutie, din densitate : ro= m/v
m= 5mlx0,973g/ml =4,865g solutie     1cmcub=1ml
-calculez masa de amoniac dizolvat in aceasta masa solutie
c/100= md/ms
6,12/100= md/4,865--> md=0,2977gNH3
-calculez moli NH3
n(niu)= 0,2977g/17g/mol=0,0175mol NH3
-calculez moli HCl care  neutralizeaza  NH3
NH4OH  +   HCl---> NH4Cl +H2O
0,0175........0,0175 mol
-calculez Vs in care se afla acesti moli HCl
c,n=c,m= n/Vs
2=0,0175/ Vs----.> Vs=0,00875 l= 8,75 ml sol,HCl 2n