ACIDS AND BASES

You are conducting an experiment to test the properties of acids and bases using vinegar, baking soda, and a pH indicator. You observe the following:

• Vinegar has a pH of 3.

• Baking soda solution has a pH of 9.

• Mixing them produces bubbles and changes the solution's pH to 7.

Question 1: Which of the following best describes the reaction?

• A. A base reacting with water to increase pH.

• B. An acid reacting with a base to neutralize each other.

• C. An acid reacting with a metal to release hydrogen gas.

• D. A base reacting with a metal to form a salt.

The pH change from 3 (acidic) and 9 (basic) to 7 (neutral) indicates a neutralization reaction, where the acid (vinegar) reacts with the base (baking soda) to produce water and carbon dioxide gas.

Question 2: If the final solution is tested with red and blue litmus paper, what will be the result?

• A. Both papers remain unchanged.

• B. Red litmus turns blue; blue litmus remains blue.

• C. Red litmus remains red; blue litmus turns red.

• D. Both papers remain unchanged because the solution is neutral.

Question 3: A scientist tests three solutions with pH values of 2, 7, and 12. Which of the following statements is correct?

• A. The solution with pH 2 is basic.

• B. The solution with pH 7 is acidic.

• C. The solution with pH 12 is basic.

• D. All solutions are neutral.

Question 4: Which of these household substances is most likely to have a pH of 10?

• A. Lemon juice

• B. Vinegar

• C. Baking soda solution

• D. Milk

Question 5: During a neutralization reaction, which products are always formed?

• A. Salt and hydrogen gas

• B. Water and salt

• C. Carbon dioxide and water

• D. Hydrogen gas and oxygen

Question 6: A red cabbage indicator turns green in a solution. What can you infer about the solution?

• A. It is neutral.

• B. It is acidic.

• C. It is basic.

• D. It contains a metal.

Question 7: Which method would be best to accurately measure the pH of a solution?

• A. Tasting the solution

• B. Using a pH meter

• C. Observing the color of the solution

• D. Testing with distilled water

Question 8: If 10 mL of an acidic solution is diluted with 90 mL of water, what happens to its pH?

• A. It increases.

• B. It decreases.

• C. It stays the same.

• D. It becomes neutral.

Question 9: Which pH value would indicate the strongest acid?

• A. 6

• B. 2

• C. 7

• D. 10

Question 10: What happens to the pH of a basic solution when a small amount of acid is added?

• A. It becomes more basic.

• B. It stays the same.

• C. It decreases.

• D. It becomes neutral.