How is it possible to suck up lemon soda through a straw ?

When you suck air from your mouth you are actually reducing the air pressure at your mouth and the mouth is connected to the lemon soda through straw. Now lemon soda is exposed to the atmospheric pressure and hence has higher pressure than the mouth. So the force acting on the lemon soda du to atmosphere is more compare to the force from the mouth. Hence the lemon soda moves to your mouth.