-calculez masa si mol NaOH
c=mdx100/ms
40/100= md/200----> md=80gNaOH
n=m/M
n= 80g/40g/mol= 2molNaOH
claculez mol gaz din ecuatia
1mol.......................1mol
NaOH+ NH4Cl---> NH3↑+H2O+NaCl
2mol....................n=2mol
V=nxVm
V= 2molx22,4l/mol=............................calculeaza !!!!