Question

If is formation of curd from milk a chemical change why

Answer 1

During the formation of Curdfrom the milk the chemicalcomposition is changed, so it is considered to be chemical change. Once Curd formed from Milk it cannot revert back to milk, so it is an irreversible change. Due to the lactobacillus bacteria the curd formation takes place .

Answer 2

The formation of curd is chemical change because it cannot againn  return to it's original state ( milk)