Final answer:
To ensure the volume of titrant is about 25 mL during titration of a 25.00 mL sample, adjust the titrant concentration to match the stoichiometry of the reaction with the sample. Precise measurements and proper techniques are imperative for accuracy.
Step-by-step explanation:
To ensure that the volume of the titrant is approximately 25 mL when titrating a 25.00 mL sample with significantly different concentrations, the concentration of the titrant should be adjusted so that it is equivalent on a stoichiometric basis to the concentration of the titrated sample.
For example, if the titrant is more concentrated than the sample, you would use less of the titrant, and if it is less concentrated, you would use more.
The key is to use the stoichiometry of the reaction to calculate how much titrant is needed based on the concentration of the sample being titrated.
For instance, in a titration where you begin with 25.00 mL of 0.100 M HCl or CH3CO2H, which provides 0.00250 mol of substance, you should add an equivalent amount of moles of a 0.100 M NaOH titrant to reach the equivalence point.
If both the sample and the titrant are 0.100 M, then you would expect to use about 25.00 mL of the titrant to reach the equivalence point where the moles of acid and base are equal.
It's important to make precise measurements of the titrant, typically using a burette, and estimating the volume reading correctly by observing the meniscus at eye level and using a graduated cylinder when necessary.