When a pinch of sodium hydrogen carbonate is added to acetic acid in a test tube, there are two observations `:`
(i) Brisk effervescence
(ii) Evolution of a colourless and odourless gas which is `CO_(2)`
`CH_(3)COOH(aq)+NaHCO_(3)(s) rarr CH_(3)COONa(aq)+H_(2)O(l)+CO_(2)(g)uarr`