I definitly believe the answer is c. 2
Answer: 
Explanation:
Heat of reaction or enthalpy change is the energy released or absorbed during the course of the reaction.
It is calculated by subtracting the enthalpy of reactants from the enthalpy of products.

= enthalpy change = ?
= enthalpy of products
= enthalpy of reactants
For the given reaction :



Answer:
As an example of the processes depicted in this figure, consider a sample of water. When gaseous water is cooled sufficiently, the attractions between H2O molecules will be capable of holding them together when they come into contact with each other; the gas condenses, forming liquid H2O. For example, liquid water forms on the outside of a cold glass as the water vapor in the air is cooled by the cold glass.
Explanation:
Hopefully that helps!
Okay so because of the difference in density a simple method for telling the difference between the two is to put a sample in a container with oil, because water has a higher density than the oil it would sink to the bottom but alcohol on the other hand is lighter than oil and would float on top of the oil.
However with this question I think that what you would do is use the ice to find out what the substance is, it would float on top of the liquid if it were water because the water is denser than ice but the ice would sink if it was alcohol because the alcohol is less dense than ice.
I hope this helps you, good luck : )