Question

State the observation seen, when milk in a dish is kept aside for a few hours or more. Is the change which occurs- Physical Change or Chemical Change. Give reasons.

Answer 1

The change which is seen is a chemical change. Here the milk doesnot remain as milk but the bacteria grown converts the milk to cottage cheese. From the cottage cheese, we can't get back the milk. Hence the reaction which is given is a chemical change.

Answer 2

Observations are like the milk will be no more as a milk after keeping the milk for a few hours or more it will be converted into cottage cheese . So, after observing we will be seeing that milk changing into cottage can't be reversed after as a milk ( original substance ) and thus be called as a chemical change.....

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