The reaction that we can perform in the hands-on activity is the reaction between vinegar and baking that is acetic acid and sodium hydrogen carbonate.
This reaction results in the formation of bubbles and turned lime water milky. The lime turned milky due to evolution of carbon dioxide gas. And the temperature of the test tube in which vinegar and baking soda is kept, got lowered. Due to this decrease in temperature, this reaction is classified as endothermic reaction.