C6H6 + HOSO3H ⇒ C6H5-SO3H + H2O
solutia de acid : initial - ms(i ); ci = 90%; macid = 0,9ms(i)
au reactionat : 5 moli H2SO4 m = 5·98 = 490g
final : ms = ms(i) - 490 + 5·18 (apa din reactie); c = 85%
md = md (i) - 5·98
[0,9ms(i) - 490] / [ms(i) - 400] ·100 = 85
85ms(i) - 400·85 = 90ms(i) - 49000 5 ms(i) = 15000 ⇒ ms(i) = 3000g