Calculate the required mass, dissolve and transfer every portion into a volumetric flask, make to the mark and invert before using a mean titre and mole ratio.
Sodium hydroxide solution reacts with carbon dioxide in the air and should be standardised before use. Ethanedioic acid may be used for this standardisation.
A standard solution of ethanedioic acid, (COOH)2, is prepared.
- 2.40 g of solid ethanedioic acid is dissolved in approximately 100 cm3 of deionised water in a beaker.
- The solution is transferred into a 250.0 cm3 volumetric flask and made up to the mark with deionised water.
Give a possible reason why any solution remaining in the beaker is washed into the volumetric flask before making up to the mark.
(1)
An answer that makes reference to one of the following points
- All the acid/reactant/solid/solution/substance weighed out should be added / transferred (to the flask) (1)
Or
none of the acid/reactant/solid/solution/substance weighed out/solution should be left behind (in the beaker)
Or
the solution remaining in the beaker will contain some dissolved ethanedioic acid/ (if washings not added) the solution concentration will be lower
Or
to ensure the amount of acid in the solution is known accurately
Allow"so that all of the solution is transferred"
Ignore just "transfer losses" just "to ensure accuracy"