M,=56g/mol butena
n= 16,8g/56g/mol=0,3mol butena
1mol ...........4mol
CH3-CH=CH-CH3 +4O---> 2CH3COOH
0,3mol....................n=1,2molO
1mol.........................................................................3mol
K2Cr2O7+4H2SO4-->K2SO4+Cr2(SO4)3+4H2O+3O
n=o,4mol.....................................................................1,2mol
c=n/V----> 2= 0,4/V----> V=0,2 L=200ml solutie