Question

what do you observe when you drop a few drops of acetic to a test tube containing the sodium hydrogen carbonate

Answer 1

Heya friend!!
Rajdeep here....

Whenver you react an acid with a carbonate or bicarbonate salt, brisk effervescence takes place as carbon dioxide gas is evolved.

Acetic acid, though a weak one, is an acid.
So when you drop it on sodium hydrogen carbonate, the following reaction takes place:

CH3COOH + NaHCO3 --------> CH3COONa + H2O + CO2
Sodium acetate, water and Carbon dioxide are formed.
The CO2 gas bubbles out through the sodium acetate solution. Hence, brisk effervescence (bubbling) takes place.

Thanks!!

Answer 2

water, sodium acetate, and CO2 will be formed. a brisk effervescence will be observed due to formation of CO2.
sodium acetate salt is a colourless crystalline salt which will dissolve in water.
the reaction is as follows:
CH3COOH + NaHCO3 ---> CH3COONa + H2O + CO2