Q4.107 P - Chemistry: Molecular Nature Of Matter And Change

Question

Describe what happens on the molecular level when acetic acid dissolves in water.

Step-by-Step Solution

Answer

You need to describe what happens on the molecular level when acetic acid dissolves in water.

Step 1: Solution of the problem

At the molecular level, acetic acid dissolves in water and produces H₃O⁺ and CH₃COO^- ions which again associates and forms CH₃COOH and H₂O. The equilibrium is reached after 2% ionization of CH₃COOH.

Step 2: Explanation of the solution

Acetic acid dissolves in water and produces H₃O⁺ and CH₃COO^- ions which again associate and forms CH₃COOH and H₂O. 

Hence, the equilibrium can be written as

$C{H}_{3}COOH\left(aq\right)+H_{3}O\rightleftharpoons H_3{O}^{+}\left(aq\right)+C{H}_{3}CO{O}^{-}\left(aq\right)$

Step 3: Explanation of the equilibrium

Weak acid CH₃COOH dissolves in water and forms H₃O⁺ and CH₃COO^- ions. As it is a weak acid, so less amount of H₃O⁺ and CH₃COO^- ions are produced. When there are enough concentration of H₃O⁺ and CH₃COO^- ions are present in the reaction mixture, and then they re-associate and forms CH₃COOH and H₂O. 

 

After some time, the rate of forward and backward reaction becomes same and the equilibrium reached.

Step 4: Conclusion

At the molecular level, acetic acid dissolves in water and produces H₃O⁺ and CH₃COO^- ions which again associates and forms CH₃COOH and H₂O. The equilibrium is reached after 2% ionization of CH₃COOH.