Question

This Russian leader proved to be last Soviet general secretary.

Answer 1

MilkhailGorbacher he is the leader who proved to be last Soviet general.
General secretary of the central committee was termed as the office of communist party which was of the soviet union. In 1920 it had involved in powerful of central committees. The committee had a few exceptions in 1929 until its dissolution. This is because the communist party of the soviet union and Soviet government were controlled by both.

Answer 2

The answer would be:

Mikhail Sergeyevich Gorbachev proved to be the last Soviet general secretary.

He was the general secretary of the Communist Party of the Soviet Union.

Hope this helps. :)