1. If a student fails to remove a large air bubble in the buret before beginning the titration, what will be the effect on the volume of titrant required to reach the titration endpoint?
A. The student will record a volume that is SMALLER than it should be for a proper titration.
B. The student will record a volume that is EQUAL TO a proper titration.
C. The student will record a volume that is LARGER than it should be for a proper titration.
3. When using a pipet and pipet bulb, a right-handed student should:
A. Hold the pipet in his right hand at the TOP of the glass and the bulb in his left hand.
B. Hold the pipet in his right hand at the BOTTOM of the glass and the bulb in his left hand.
4. A student stopped her titration when she observed the pink color persist for 30 seconds, but she failed to swirl the flask. Were her volumes of titrant used too large, too small, or still right?
Answer: Is it still right?
7. An unknown solutionis found in the lab. If the solution turns pink when phenolphthalein is added, what does that tell you about the pH of the solution?
A. the solution is basic
B. solution is acidic
C It tells you nothing about the acidity and basicity
D. The solution is neutral.
1. Wouldn't the volume be larger bc it takes up space and it will be added to the volume
3. shouldn't it be A
4. Still right?
7. It tells you nothing about the acidity and basicity
Are these right or wrong?
4. The answer is either too small or too large but I am unsure.
7. The solution is either basic, acidic, or tells you nothing about either, but I'm also unsure.
Still correct choice for 4 is wrong and solution is neutral is wrong for 7.
1 and 3 are right. 4 and 7 are wrong. Phenolphthalein turns pink when pH is about 9 (range about 8 to 10) and that is basic. If the solution was pink for 30 sec that means the solution AT THAT ONE SPOT in the flask was OK but the entire solution was not titrated; therefore, most must be added. So the answer is that the volume of titrant was too small at that point.
1. If a student fails to remove a large air bubble in the buret before beginning the titration, the effect on the volume of titrant required to reach the titration endpoint will be that the student will record a volume that is LARGER than it should be for a proper titration. The air bubble takes up space in the buret, displacing the volume of titrant, causing the student to initially dispense more titrant than necessary. To get the correct volume, the student should remove the air bubble by tapping the buret gently or by using a small amount of the titrant to fill the buret and displace the air bubble.
3. When using a pipet and pipet bulb, a right-handed student should hold the pipet in his right hand at the TOP of the glass and the bulb in his left hand. This allows for better control and stability while pipetting. The student should use the pipet bulb to create suction and draw the liquid into the pipet, and then release the suction to accurately dispense the desired volume.
4. If a student stopped her titration when she observed the pink color persist for 30 seconds but failed to swirl the flask, her volumes of titrant used may still be right. Swirling the flask helps ensure complete mixing of the reactants and a proper endpoint determination. Without swirling, it is possible that the pink color persisted due to uneven mixing, and the endpoint may not have been accurately determined. However, if the volumes of titrant used were consistent with previous titrations and the student was confident in the outcome, the volumes may still be considered acceptable.
7. If the unknown solution turns pink when phenolphthalein is added, that indicates that the solution is basic. Phenolphthalein is a pH indicator that changes color in the presence of a basic or alkaline solution. Pink coloration suggests that the pH of the solution is above the neutral range.