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?

A milkman adds a very small amount of baking soda to fresh milk. Why does he shift the pH of the fresh milk from 6 to slightly alkaline

Why do we add little amount of butter milk to get curd ?

Fresh milk has a pH of 6. Explain why the pH changes as it turns into curd.

A glass full of hot milk is poured on the table. It begins to cool gradually. Which of the following is correct? (a) The rate of cooling is constant till milk attains the temperature of the surrounding. (b) The temperature of milk faills off exponentially with time. ( c) While cooling, there is a flow of heat from milk to the surrounding as well as from surrounding to the milk but the net flow of heat is from milk to the surrounding and that is why it cools. (d) All three phenomenon, conduction, convection and radiation are responsible for the loss of heat from milk to the surroundings.

Take three bowls and mark as A,B,C . Pour lukewarm milk in bowl. A hot milk in bowl B, cold milk in bowl C. Add one tea spoon of curd or butter milk in three bowls and stir them slightly. Cover the bowls with lids. Keep the bowls undisturbed for five to six hours. In which bowl milk turned into curd? Give your reasons.