Question

When we use a burette in an acid base titration, how many drops are equivalent to a 13.0mL volume?

Answer 1

We are given a burette in this question. We will consider the normal volumetric glass pipette with manually operated cork to disperse the titrant. To calculate the no. of drops in 13.0 mL will be to first find the volume of 1 drop of liquid from the burette.

Complete answer:
The drop is a unit used for measurement of volume. The volume of liquid dispersed as a single drop from a dropper or a drip chamber. Patients in hospitals are often given medicines in this dropwise unit. The abbreviations used are gt or gtt meaning ‘Drop’ in Latin. The volume of the drop is not well defined, as it depends on the technique used to produce a drop, and also on the gravitational field, viscosity, density and the surface tension of the liquid. The minim was the smallest unit of measure in the 19th century. The volume of minim was measured using a graduated pipette or a millimeter. The volume was found to be equal to rounded off to exactly 0.05mL. This is the volume of one drop of titrant from the burette. This can be written as:
$1drop = 0.05mL$
$1mL = \dfrac{1}{{0.05}} = 20drops$
We are given 13.0mL of titrant. The no. of drops equivalent to 13.0mL will be equal to: $13mL = 20 \times 13 = 260drops$
Therefore, 260 drops are equivalent to a 13.0mL volume This is the required answer.

Note:
Burette is an analytical instrument commonly used for titration. The least count of a burette is 0.01mL, but it can vary depending on the sensitivity of the burette. A burette provides the volume measurement precisely because of its smaller meniscus and up to two decimal places.