Mixing Ethanol and Water

In summary: The difference in strength of the bond is measured by how much heat is liberated when the two substances are mixed.
  • #1
nirmaljoshi
6
0
Why heat is generated when ethanol is mixed with water? Please also explain why the existing hydrogen bond of water disintegrated to accommodate ethanol molecule?
 
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  • #2
Ethanol molecules are much smaller in size than the water molecules and as a consequence some of the ethanol molecules tend to cram in between the water molecules, thus breaking the hydrogen bond.
Enthalpy of mixing water and ethanol is -ve(exothermic), hence heat is liberated.
 
  • #3
sagarbhathwar said:
Ethanol molecules are much smaller in size than the water molecules and as a consequence some of the ethanol molecules tend to cram in between the water molecules, thus breaking the hydrogen bond.

Water molecules are significantly smaller than ethanol molecules.

Water: H2O
Ethanol: CH3-CH2-OH
 
  • #4
Oh I am extremely sorry. It exactly the other way around. Swap places with ethanol and water :)

Thanks
Sagar
 
  • #5
sagarbhathwar said:
Enthalpy of mixing water and ethanol is -ve(exothermic), hence heat is liberated.

My question is why it is exothermic? As you said, "Ethanol molecules are much smaller in size than the water molecules and as a consequence some of the ethanol molecules tend to cram in between the water molecules, thus breaking the hydrogen bond."

But after mixing, water and ethanol again forms the hydrogen bond and hence they remain in stable form. That is, one hydrogen bond is broken and another is formed. If so, there should not be any liberation of energy.

Please correct me if i am on wrong way.
 
  • #6
Yes. H-bond is formed again between hydrogen and water molecules but the strength of this bond is weaker than that between water-water molecules. So I am guessing that is why some heat is liberated.
Always consider difference in strength of the bonds. Not just the bonds.
 
  • #7
Thanks.

Could you please briefly direct me how the difference in strength of bond is measured?
 

What is the effect of mixing ethanol and water?

Mixing ethanol and water results in a solution with properties that differ from those of the individual components. This is because the molecules of ethanol and water interact with each other, forming new bonds and changing the overall properties of the solution.

What is the ratio of ethanol to water when mixing them?

The ratio of ethanol to water when mixing them can vary depending on the desired concentration of the solution. An example of a commonly used ratio is 70% ethanol and 30% water, which is often used as a disinfectant.

Can ethanol and water completely mix together?

Yes, ethanol and water are completely miscible, meaning they can mix together in any proportion. This is because the molecules of ethanol and water have similar polarities and can form intermolecular bonds with each other.

What happens if you mix equal parts of ethanol and water?

If you mix equal parts of ethanol and water, you will get a solution with a concentration of approximately 50%. This solution is commonly used as a solvent and can also be used as a disinfectant.

What are the uses of mixing ethanol and water?

Mixing ethanol and water has many uses. Some common ones include creating alcoholic beverages, as a disinfectant for cleaning and sanitizing, as a solvent for various substances, and as a fuel for vehicles and other machinery.

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