Ron weasley is slightly clumsy and often makes mistakes. today he needs to heat a test tube filled with a solution. where should he apply heat to the test tube?

The answer to this question would be: C) Middle of the test tube.
The best method to apply heat to test tube is by moving it back and forth to the fire. Use test tube holder so you won't burn your hands. Tilt the tube and make sure the tube not directed to you or your friends. Don't fill the tube more than 1/2 of its maximal volume