When a molecule is going through any physical change, solid to liquid or liquid to gas, as it changes, the temperature remains constant. it does not increase or decrease, it stays at that temperature/.
For example, water evaporates/ boils at 100 C. if you are heating water to the point of boiling, it will remain 100 C until all the water evaporates. Once it becomes a gas, the temperature will continue to increase
During the evaporation of a liquid the temperature remains constant.
Explanation:
Starting with a liquid, if you heat it, its temperature increase, when it reaches the boiling point, the temperature remains constant while the liquid transform into vapor, if the heating continues, the temperature of the vapor will increase. All phase changes of pure substances are done at constant temperature.
The amount of the solute is constant during dilution. So the mole number of HCl is 2*1.5=3 mole. The volume of HCl stock is 3/12=0.25 L. So using 0.25 L stock solution and dilute to 2.0 L.
