The practice that will not help you make an accurate volume reading on a burette at the beginning of a titration is:
- Starting the meniscus exactly at 0.00 mL on the burette scale.
This is because starting exactly at 0.00 mL is actually not the most accurate approach. The initial reading can be anywhere on the scale, and trying to line up the meniscus exactly at zero is unnecessary and can lead to errors. Instead, you should read the initial volume accurately wherever it falls on the scale, to the nearest 0.01 mL, without forcing it to zero. This is supported by guidance that says "Do not waste your time trying to line up some initial volume such as 0.10 or 1.00 in the buret. Read it to + 0.01 mL wherever it happens to fall. Never start with a volume of 0.00 mL - this is the least accurate measurement on the scale because there is nothing above it to use as a reference"
. Other practices that do help accuracy include:
- Making sure the meniscus falls within the marked range on the burette.
- Reading the volume at eye level to avoid parallax error.
- Reading the volume at the bottom of the meniscus.
Errors that reduce accuracy include parallax errors (reading at an angle), misjudging the meniscus, and poor lighting conditions
. In summary, the incorrect practice is insisting the meniscus must start exactly at 0.00 mL before titration, which does not improve accuracy and can actually cause errors. Instead, accurately record the initial volume wherever it is on the scale and read carefully at eye level
