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.

a mercury barometer is a device that uses the physical properties of mercury in a tube to measure barometric pressure. mercury barometers are used for : -

1. measurement of atmospheric pressure  

2. determining the altitude of a place

3. weather forecasting

4. calibration and checking of aneroid barometers

5. application in fluid mechanics

6. measurement of pressure in aircrafts

7. surface weather analysis

8. preparation of barographs

9. usage in physical sciences like physics, astronomy & chemistry

10. preparation of aircraft altimeters

characteristics of mercury barometer : -

1.used to define and measure atmospheric pressure.

2.on the average at sea level the column of mercury rises to a height of about 760 mm.

3.this quantity is equal to 1 atmosphere.

4.it is also known as standard atmospheric pressure.

5.a barometer in which the weight of a column of mercury in a glass tube with a sealed top is balanced against that of the atmosphere pressing on an exposed cistern of mercury at the base of the mercury column, the height of the column varying with atmospheric pressure.