Answer:
It is a chemical change
Step-by-step explanation:
The combination of sodium hydroxide and fat yields soap and glycerine.
We have to remember that one of the characteristics of a chemical change is that new substance(es) is/are formed. We have to look out for this when considering any process.
We can see here that new substances were formed (soap and glycerine). Based on this, we can assert that a chemical change has taken place.