calculez masa de acid din solutia data
c=mdx100/ms-----> md= 20x200/100g= 40gH2SO4
calculez masa de BaSO4 din ecuatia chimica
1mol........................................1mol sau, in grame
H2SO4 + BaCl2--------> BaSO4↓ + 2HCl
98g..............................................233g
40g.....................................................x=.......................calculeaza!!!!!!
(M,H2SO4= 98g/mol M,BaSO4= 133g/mol)