DPP -10S21

INDICATOR, pH & DILUTION

1. You have been provided with three test tubes. One of them contains distilled water and the other two contain an acidic solution and a basic solution, respectively. If you are given only red litmus paper, how will you identify the contents of each test tube?

2. Why do acids not show acidic behaviour in the absence of water?

3. What is the correct way to Dilute an Acid?

4. You have two solutions, A and B. The pH of solution A is 6 and pH of solution B is 8. Which solution has more hydrogen ion concentration? Which of this is acidic and which one is basic?

5. What effect does the concentration of H+ (aq) ions have on the nature of the solution?

6. Do basic solutions also have H+ (aq) ions? If yes, then why are these basic?

7. Under what soil condition do you think a farmer would treat the soil of his fields with quick lime (calcium oxide) or slaked lime (calcium hydroxide) or chalk (calcium carbonate)?

8. Fresh milk has a pH of 6. How do you think the pH will change as it turns into curd? Explain your answer.

9. 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?

10. Curd is not kept in copper and brass utensils. Why?