What type of change is involved in tautomerism ?

Explanation

**Step-by-Step Solution:**

1. **Understanding Tautomerism:**
Tautomerism is a chemical phenomenon where two isomers (tautomers) can interconvert through the movement of a proton and a shift of a double bond. It typically involves the transformation between a keto form (with a carbonyl group) and an enol form (with a hydroxyl group adjacent to a double bond).

2. **Example of Tautomerism:**
Consider acetone (CH3C(=O)CH3) as an example of keto-enol tautomerism. In this case, the keto form is acetone, and the enol form is an enol derivative of acetone.

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