Soda drinks bubble when the bottle is opened because:

(1) the temperature of the soda increases.
(2) exposure to atmospheric pressure squeezes the carbon dioxide from solution.
(3) the partial pressure of carbon dioxide above the solution is reduced.
(4) atmospheric nitrogen molecules displace carbon dioxide molecules.
(5) the henry's law constant changes due to the change in pressure.

(3) the partial pressure of carbon dioxide above the solution is reduced.

Explanation:

We know , Soda water contains pressured carbon dioxide pressured with cap because we know according to Henry's law partial pressure of the gas is directly proportional to pressure applied. Therefore, is pressurized in the bottle.

But as we open the bottle the pressure decreases the excess (and air) escapes producing effervescence and partial pressure of decreases. ( Because of Henry's Law)  

Hence, it is the required solution.