why heat is formed when methanol mixed with water?

Question

when methanol mixed with water heat is formed.what is behind it 

Answer 1

When methanol is mixed with water, a miscible mixture (solution) is formed.  What is going on during this process?

Both water (H2O) and methanol (CH3OH) exhibit hydrogen bonding between like molecules. So, both liquids are held together by H-bonding. Now, when mixed, several things happen. First, the H-bonding between water molecules are broken, as is the case between methanol molecules.  This is an ENDOTHERMIC process.  Then, H-bonds are formed between some methanol molecules and some water molecules.  This is an EXOTHERMIC process.The latter process predominates mainly because methanol can H-bond to water easier than to itself.  Thus, the overall process is EXOTHERMIC and heat is given off to the surroundings.

 

Answer 2

Sorry, I don't know the specific answer, but, when heat is released, it's because a more stable configuration, with lower energy, has been formed.

 

The methanol molecules must make a lower energy structure with the water molecules.