Plz answer all with explanations.

1) Test tube 3, the third one.

2)

Explanation:

The first(1) test tube is Cold H2O(Water/dihydrogen monoxide), and 0.5 miligrams of Sodium Carbonate(Na2CO3).

The second(2) test tube is Cold H2O(Water/dihydrogen monoxide), and 0.5 miligrams of Sodium Carbonate(Na2CO3) with Citric acid(C6H8O7).

The third(3) test tube is Hot H2O(Water/dihydrogen monoxide), and 0.5 miligrams of Sodium Carbonate(Na2CO3).

The fourth(4) test tube is Hot H2O(Water/dihydrogen monoxide), and 0.5 miligrams of Sodium Carbonate(Na2CO3) with Citric acid(C6H8O7).

To find which test tube produces gas bubbles, evaluate the type of reaction from the given reactants by determining it's product. Reactants →(yeilds) Products.

Increasing temperature causes the concentration of a reactant to increase, while causing the concentration of a product to increase. This scenario is the exact opposite for decreasing temperature. Endothermic(heat transfer in;endo) is an increase in temperature, while Exothermic(heat transfer out;exo) is a decrease in temperature. Colder substances move slower, and will react slower while warmer substances move faster, and react faster. Just as you warm up when you run faster. This is all based on thermodynamics(heat energy and kinetic(motion) energy resulting in movement in particles). Temperature is the measure of average kinetic energy in an object. Surface tension decreases as temperature rises, and increases as temperature falls. Therefore more boubles with an endothermic reaction because heat is transferred within the substance. And thus a greater reaction.

its c not d   tell me if that´s correct