so if I breed a male pikachu with volt tackle with a female pikachu will the pichu know volt tackle
No, you can only get a Pichu with Volt Tackle if any of the parents are holding the Light Ball. Example: If you leave a Male Pikachu holding a Light Ball and a Female Pikachu in the Day-Care, the offspring will automatically know Volt Tackle.
Yes, the offspring would learn volt tackle.
But, JIC(just in case), have the male pikachu hold the light ball