How would you show that setting of curd is a chemical change?
Dear Student,
During setting of curd lactose is converted to lactic acid by bacteria, this leads to lowering of pH (due to formation of acid), thus can be called as chemical change. Also, Once the curd is formed, milk cannot be re-obtained from it (irreversible change). Also, both milk and curd have different properties. Since these are the properties of a chemical change, setting of curd is a chemical change.
Thus, setting of curd or formation of curd is a chemical reaction.
Regards