Question

Conversion-ethanol to 2-Hydroxy-3-but enoic acid

Answer 1

This is clearly not so simple. Chlorination suggested by some is far too uncontrolled and I doubt would be effective since the carboxylic group is likely to interfere with the free radical mechanism.

I would agree with Jim Griepenburg, that some kind of enolisation is required. Ethanoic acid would not really be the choice starting point.