the trying of impeachments is done by who?

That depends on whether you are talking about the US government, or a state government. This site relates to US govt.

http://www.jiskha.com/display.cgi?id=1233860019

oooppppssss! http://library.duke.edu/blogs/answerperson/2004/09/30/impeachment/

The trying of impeachments is done by the Senate. To find this answer, you can refer to the United States Constitution. In Article I, Section 3, Clause 6, it states that "The Senate shall have the sole power to try all impeachments." Therefore, the Senate is responsible for hearing the evidence, conducting the trial, and ultimately deciding whether to convict or acquit the impeached official.