Question

Explain why melting of butter is reversible whereas curdling of milk is irreversible.

Answer 1

Melting of butter is a reversible change because on freezing, the melted butter changes back to its solid form. Whereas curdling of milk is an irreversible change because on curdling, milk changes to curd and cream, and gets spoilt when not refrigerated, and cannot be changed back to milk by any process.