11. Fresh milk has a pH of 6. How do you think the pH will change as it turns into curd? Explain your answer. 12. 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? 13. Plaster of Paris should be stored in a moisture-proof container. Explain why? 14. What is a neutralisation reaction? Give two examples. 15. Give two important uses of washing soda and baking soda. Group Activity (1) Prepare your own indicator Crush beetroot in a mortar. Add sufficient water to obtain the extract. Filter the extract by the procedure learnt by you in earlier classes. Collect the filtrate to test the substances you may have tasted earlier. to four test tubes in a test tube stand and label them as A.B.C and D. Pour dhaking soda solution
Answers
Explanation:
The pH value of
- Basic solution is greater than 7.
- Neutral solution is equal to 7.
- Acidic solution is less than 7.
The pH value of milk is 6 since it is acidic in nature. When the milk is converted into curd due to the action of bacteria, lactic acid is formed which is more acidic in nature. Therefore the pH value of the milk is reduced as it turns to curd.
Answer:
11.
Fresh milk has a pH of 6.When milk changes into curd, the pH value will change , The pH value of milk is 6 since it is acidic in nature. When the milk is converted into curd due to the action of bacteria, lactic acid is formed which is more acidic in nature.
13.
Plaster of Paris should be stored in a moisture-proof container because the Plaster of Paris, a powdery mass, absorbs water (moisture) from the environment to form a hard solid substance known as Gypsum.
14.
The neutralization reaction is the one in which an acid reacts with an equimolar amount of base to give salt and water. The example could be a reaction between any strong acid and a base. The sodium chloride formed is a result of neutralization reaction.