Define the term brisk effervescence?

Hint: Effervescence is a general term that we may come across while doing a chemistry practical. Brisk means to have a rapid action, while effervescence is the phenomena of having fizz like bubbles in anything. Brisk effervescence is an example that we can observe while having a carbonated drink due to the gas in it.

Complete answer:
There are certain reactions in chemistry that lead to the formation of products that produce white frizz or bubbles rapidly. This formation of rapid bubble-like liquid is a phenomenon called effervescence. When this happens rapidly it is termed brisk effervescence. This happens due to the formation of a gas carbon dioxide $C{{O}_{2}}$. As the chemical reaction proceeds, when the product carbon dioxide is formed it causes a rapid effervescence as gases have lower solubility in liquids so they evolve and create brisk effervescence.
The example of brisk effervescence is observed when a reaction is carried out between sodium bicarbonate and acetic acid. The reaction produces carbon dioxide that evolves through brisk effervescence. The reaction is:
$C{{H}_{3}}COOH+NaHC{{O}_{3}}\to C{{H}_{3}}COONa+C{{O}_{2}}\uparrow +{{H}_{2}}O$
Hence, brisk effervescence is defined as the rapid evolution of carbon dioxide creating bubbles in a chemical reaction.

Note:
The reaction to test that carbon dioxide is evolved through effervescence is the test where carbon dioxide is passed through lime water that turns lime water into a milky appearance. The reaction is $Ca{{(OH)}_{2}}+C{{O}_{2}}\to CaC{{O}_{3}}\downarrow +{{H}_{2}}O$ the calcium carbonate precipitate is white and milky in appearance that confirms the evolution of carbon dioxide.