A:Answer Yes, If your earphones have been previously paired to your smartphone/tablet the earphones should automatically connect when you turn them ON, they should automatically disconnect when you turn them OFF.
If you take them off in the middle of a song the earphones won't stop playing, you will have to stop the music manually,
The earphones play only through one side when on a phone call, both sides when listening to music, the sounds going through both ears but the sounds on one ear and the other are different as they are stereo.