Question

When vinegar (CH_3COOH) and baking soda (NaHCO_3) are combined, the mixture spontaneously undergoes an endothermic reaction while releasing CO_2 gas. The test tube would feel ______ and delta G would be ________ .

A. Hot, positive
B. Hot, negative
C. Cold, positive
D. Cold, negative

Answer 1

The test tube would feel cold and delta G would be negative, indicating an endothermic reaction that proceeds spontaneously. The reaction is also a Brønsted-Lowry acid-base reaction with acetic acid donating a proton to the bicarbonate ion.

Step-by-step explanation:

When vinegar (CH3COOH) and baking soda (NaHCO3) are combined, the test tube would feel cold, and delta G would be negative. This is because the reaction between vinegar and baking soda is an endothermic reaction, as indicated by the sensation of coldness due to the absorption of heat from the surroundings. The delta G, which denotes Gibbs free energy change, would be negative, signifying that the reaction proceeds spontaneously under constant temperature and pressure.

A balanced equation for this reaction would be:
NaHCO3(s) + CH3COOH(aq) → CO2(g) + H2O(l) + NaCH3COO(aq).

This is a Brønsted-Lowry acid-base reaction, where a Brønsted-Lowry acid is a substance that donates a proton, and a Brønsted-Lowry base is a substance that accepts a proton. In this case, acetic acid donates a proton to the bicarbonate ion.