To convert Propanal to 2-Hydroxypropanoic acid, we need to first oxidize Propanal to Propanoic acid. This can be done by using a strong oxidizing agent such as potassium permanganate or chromium trioxide in the presence of acidic or basic conditions. The reaction can be represented as follows:




Once we have Propanoic acid, we need to convert it to Lactone. This can be done by using a dehydrating agent such as thionyl chloride or phosphorus pentoxide. The reaction can be represented as follows:




Finally, we need to hydrolyze the Lactone to obtain 2-Hydroxypropanoic acid. This can be done by using a strong base such as sodium hydroxide or potassium hydroxide. The reaction can be represented as follows:




The overall reaction can be represented as follows:



Therefore, by following these steps, we can convert Propanal to 2-Hydroxypropanoic acid.