Lab report Conclusions

Please I need assistance with the conclusion from my lab report. We were doing an oxidation experiment to obtain a benzoic acid with melting point of 121-123 C but we got a very impure substant that did not melt at more than 300 C. I need help explaining what couldve gone wrong during the process or what I couldve done different. I am attaching the lab report that I need to fillout and the steps that I did.