When ammonium chloride is dissolved in water in a test tube, the tube feels colder showing that

The process is endothermic when ammonium chloride is dissolved in water in a test tube. When ammonium chloride is dissolved in water, it absorbs heat from the surroundings to break apart the ionic bonds between the ammonium and chloride ions. This means that the process requires energy to take place and absorbs heat from the surrounding environment. As a result, the test tube containing the solution feels colder to the touch, indicating that heat is being transferred from the surroundings to the solution. In summary, the cooling effect observed when ammonium chloride is dissolved in water in a test tube is due to the endothermic process of breaking apart ionic bonds, which absorbs heat from the surroundings.