Answer:
1. by not avoiding air bubbles from being trapped in the burette or pipette when filling them
2. not cross-checking the burette if it's slanted or vertically clamped
3. forgetting to rinse the pipette or burette with the solution to be used
4. not considering to take readings from the bottom of the meniscus with the eye level
5. finally, adding more than three drops of indicators to the pipetted solution
Explanation:
1. because the air bubbles will be mistakenly considered as part of the amount of the solution taken instead of that actually used up, and a higher titre value would be obtained
2. because if it's slanted, the acid level will be titled to one side and wrong reading will be recorded
3. rinsing to avoid diluting the acid or base with water that wets the burette or pipette
4. to avoid error of parallax and helps you to obtain accurate readings
5. excess burette solution than would normally have been consumed would be used up to change the colour of the indicator
