Question

A milkman adds a very small amount of baking soda to fresh milk.
(a) Why does he shift the pH of the fresh milk from 6 to slightly alkaline?
(b) Why does this milk take a long time to set as curd?

Explain briefly
Class 10​

Answer 1

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a) When the milk is made more alkaline by adding a base to it, it is basically done to prevent it for more time to turning to curd. That’s why milkman shifts the pH of fresh milk to slightly alkaline by adding a very small amount of baking soda to it as baking soda is alkaline in nature and it neutralizes the acidic nature of milk.

b) As this milk is slightly more alkaline than other, therefore, acid produced to set into curd will be neutralized by baking soda added by milkman. Hence, this milk takes a longer time to set as curd.

Answer 2

Answer:

(a) By adding a very small amount of baking soda to fresh milk, the milkman keeps the milk unspoiled for little more time than usual time.As the pH value increases the milk turns to slightly alkaline,  

(b) As baking soda is added, it turned into a base. But curd needs acidic condition to set. Hence this milk takes a long time to set as a curd.