The rxn is unbalanced. Written in terms of the chemical formulas, the rxn is:
C5H9NO4 + H2Se -> C2H3O2 + C3H6NO5S2
There are 2 Sulfurs on the right not present on the left, one selenium on the left not present on the right, and a mismatched number of oxygens. The S and Se each only appear in one reagent, so the rxn cannot be balanced by changing coefficients.
Description of the issue
The rxn is unbalanced. Written in terms of the chemical formulas, the rxn is: C5H9NO4 + H2Se -> C2H3O2 + C3H6NO5S2 There are 2 Sulfurs on the right not present on the left, one selenium on the left not present on the right, and a mismatched number of oxygens. The S and Se each only appear in one reagent, so the rxn cannot be balanced by changing coefficients.
Page
http://bigg.ucsd.edu/universal/reactions/AHSERL3
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Chrome/91.0.4472.101