Effervescent

I want to know from where the air bubbles come  when effervescent tablets are put into water???

the process of bubbling as gas escapes is known as effervescence.

I got to know about the details of the process at wikipedia

Effervescence is the escape of gas from an aqueous solution. The term is used to describe the foaming or fizzing that results from a release of gas. An everyday example is seen in carbonated beverages such as soft drinks. The visible bubbles are produced by effervescence from the dissolved gas (which itself is not visible in the liquid solution).

In the lab, a common example of effervescence is seen if hydrochloric acid is added to a block of limestone. If a few pieces of marble or an antacid tablet are put in hydrochloric acid in a test tube fitted with a cork, effervescence of carbon dioxide can be witnessed.

This process is generally represented by the following reaction, where a pressurized dilute solution of carbonic acid in water releases gaseous carbon dioxide at decompression:

In simple terms, it is the result of the chemical reaction occurring in the liquid which produces a gaseous product.

Dear member thanks for posting a good question like this. An effervescent tablet has chemical components tht react wth water to release some gaseous product that appear as bubbles.

A little similar process is carbonation. Carbonation occurs when carbon dioxide is dissolved in water or an aqueous solution. This process yields the "fizz" to carbonated water and sparkling mineral water, the head to beer, and the cork pop and bubbles to champagne and sparkling wine. but here co2 is dissolved in it from earlier and tab reacts to produce gaseous pdts in effervescence.

Thanks to all of you for answering my query. But how it makes up pressure in a closed bottle? Kindly answer in terms of energy laws.