First sort out the chemical formula and write it as follows.
_ _ cro 3+_ _ C2H6O+_ _ h2so 4 = = = = _ _ Cr 2s 3 o 12+_ _ C2H4O+_ _ H2O
The sulfur in it is tandem, so mix it first.
_ _ cro 3+_ _ C2H6O+3h2so 4 = = = = 1 Cr 2s 3 o 12+_ _ C2H4O+_ _ H2O
There are two Cr's in 1Cr2S3O 12, so the first CrO3 is rationed to 2.
2 cro 3+_ _ C2H6O+3h2so 4 = = = = 1 Cr 2s 3 o 12+_ _ C2H4O+_ _ H2O
There's only H O left, so it shouldn't be difficult to match. It can be solved by observation.
For such an equation, you can also solve it like this, using the mathematical undetermined coefficient method.
acro 3+_ BC 2 H5 oh+ch2so 4 = = = = DCR 2(SO4)3+ech 3 CHO+fH2O
If the number of molecules before and after the same element is the same, the number of atoms before and after the equation can be listed as an equation.
A = 2 days before and after Cr.
3a+b+4c of o =12d+f+e.
..... I won't write the next few.
Solving this multivariate linear equation system ABCDEF is the coefficient you want, but it is troublesome, so it is not recommended. It is only used when there is no way to solve it in the exam.