When you mix vinegar and baking soda together why is it cold?

When vinegar and baking soda are mixed together, they do not produce cold. In fact, the reaction is exothermic, meaning that it releases heat. The chemical reaction between vinegar (acetic acid) and baking soda (sodium bicarbonate) produces carbon dioxide gas, water, and sodium acetate. The carbon dioxide gas bubbles out of the mixture, creating a fizzing effect. The sodium acetate is a salt that is dissolved in the water. The reaction is represented by the following equation:

CH3COOH + NaHCO3 → CO2 + H2O + CH3COONa

The enthalpy change for this reaction is -84 kJ/mol, meaning that 84 kJ of heat are released for every mole of reactants consumed. This amount of heat is not significant enough to cause a noticeable temperature change in a small volume of liquid, so the mixture does not feel cold to the touch.