When fats react with sodium hydroxide, they form soap and glycerol. This process is called saponification.

Here's a breakdown:

* Fats are triglycerides, which are esters of glycerol and fatty acids.

* Sodium hydroxide (NaOH) is a strong base.

* Saponification is a hydrolysis reaction where the ester bonds in the triglycerides are broken by the hydroxide ions (OH-) from the sodium hydroxide.

The reaction produces:

* Soap: Sodium salts of the fatty acids.

* Glycerol: A trihydroxy alcohol.

Here's a simplified chemical equation:

Triglyceride + 3 NaOH → 3 Soap + Glycerol

In summary: The reaction between fats and sodium hydroxide breaks down the fat molecules into soap and glycerol, which are both valuable products.