1.
Litmus is a common indicator used to tell whether something is an acid or a base. If you dip a piece of blue litmus paper into an acid, what color will it turn?
Correct Answer
C. Red
Explanation
When blue litmus paper is dipped into an acid, it will turn red. This is because litmus paper is a pH indicator that changes color in response to the acidity or alkalinity of a substance. Blue litmus paper is typically blue in neutral or basic solutions, but it turns red in the presence of an acid. This color change occurs due to a chemical reaction between the litmus paper and the acid, indicating the acidic nature of the substance being tested.
2.
If you dip a piece of red litmus paper into an acid, what color will it turn?
Correct Answer
C. None, it will stay red
Explanation
When red litmus paper is dipped into an acid, it will stay red. Litmus paper is used as an indicator to determine whether a substance is an acid or a base. Red litmus paper stays red in the presence of an acid, indicating that the substance is acidic. If the litmus paper were to turn blue, it would indicate that the substance is basic. In this case, since the litmus paper stays red, it suggests that the acid does not cause a color change in the paper.
3.
Phenolphthalein is another acid-base indicator. Which of these is used as an abbreviation for this indicator?
Correct Answer
B. PHTH
Explanation
Phenolphthalein is commonly abbreviated as PHTH.
4.
If you were to drop some phenolphthalein into a base, what color would it turn?
Correct Answer
D. Purple-Pink
Explanation
Phenolphthalein is an indicator that changes color based on the pH of the solution it is added to. In a basic solution, phenolphthalein turns purple-pink. This is because in a basic solution, the pH is higher, and phenolphthalein undergoes a chemical reaction that causes it to change from colorless to purple-pink. Therefore, when dropped into a base, phenolphthalein would turn purple-pink.
5.
Goldenrod paper comes as little strips, similar to litmus. If you were to dip a piece of goldenrod paper in a base, what color would it turn?
Correct Answer
D. Red
Explanation
Goldenrod paper is a type of pH indicator paper that changes color when it comes into contact with acidic or basic substances. In this case, if a piece of goldenrod paper is dipped in a base, it would turn red. Bases have a higher pH level, which causes the paper to undergo a chemical reaction and change color to indicate the presence of a base.
6.
Now on to universal indicator. What color would this turn in a very strong acid?
Correct Answer
C. Red
Explanation
Universal indicator is a pH indicator that changes color depending on the acidity or alkalinity of a solution. In a very strong acid, the pH level would be extremely low, indicating a high acidity. Universal indicator typically turns red in highly acidic solutions, indicating a pH below 4. Therefore, the correct answer is red.
7.
What color would universal indicator turn if a substance was neutral?
Correct Answer
C. Green
Explanation
Universal indicator is a chemical solution that changes color depending on the pH of a substance. It turns red in acidic solutions, green in neutral solutions, and blue or purple in alkaline solutions. Therefore, if a substance is neutral, the universal indicator would turn green.
8.
If you were to put some universal indicator in a very strong base, what color would it turn?
Correct Answer
A. Purple
Explanation
When a universal indicator is added to a strong base, it will turn purple. This is because strong bases have a high concentration of hydroxide ions (OH-) which react with the indicator causing it to change color. In the case of a universal indicator, purple is the color that indicates a strong base.
9.
One unconventional indicator is red cabbage juice. What color will this common liquid turn in a base?
Correct Answer
D. Blue-Green
Explanation
Red cabbage juice is a natural pH indicator that changes color depending on the acidity or alkalinity of a solution. In a base, the red cabbage juice will turn blue-green. This is because bases have a higher pH level, which causes the red cabbage juice to shift towards the blue-green end of the color spectrum. Therefore, the correct answer is blue-green.
10.
An indicator that you wouldn't find at home is Phenol Red. What color does this indicator turn in an acid?
Correct Answer
D. Yellow
Explanation
Phenol Red is an indicator that is commonly used in laboratories to determine the pH level of a solution. It changes color depending on the acidity or alkalinity of the solution. In an acid, Phenol Red turns yellow. This is because acids have a low pH, and Phenol Red is designed to exhibit a yellow color in the presence of acidic conditions. Therefore, the correct answer is yellow.