How to predict the product of a disproportionation reaction??

Disproportionation rxn means a same compound that undergoes oxidation and reduction simultaneously in any reaction . 

 

You can judge products by having some common knowledge of oxidation states that are most common for different elements like in manganese oxidation state general ly interchanges bw (+2,+5,+7) . Phosphorus (+3,+5,0) , oxygen f(-1,-2 0)  eg. In h2o2>>h2o+o2 oxygen in -1 goes to -2and +0 likewise for all elements (refer NCERT)

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