Providing wrong input parameters to arduino

Say i have a UNO R3 or take any Arduino for consideration.

  • What will happen if i connects VCC to NEGATIVE POLE OF DC 12V BATTERY
  • What will happen if i connects GND to POSITIVE POLE OF DC 12V BATTERY
  • What will happen if i used AC 220V INSTEAD DC 12V BATTERY

I JUST WANT TO CONFIRM, DO I NEED A BRIDGE RECTIFIER TO SAVE ARDUINO BOARD?

(deleted)