Hey Guys!

Hey Guys! So I was doing the recommended book problems for my Orgo 2 class, and one of the problems said that you can reduce NO2-->NH2 using HCl and Zn/Hg, which I understand, but then it had you go from NH2-->NO2 using CF3CO3H. I was just wondering if that was an actual thing/if the mechanism was covered somewhere/what the heck is going on? Any help is greatly appreciated, y'all are the best!