I have problem with my experiment. My experiment is acid hydrolysis of ethyl benzoate. The acid that I used is sulfuric acid. My problem is when I get the precipitate (impure benzoic acid) I have to filter it from the solution (of course) and I need to remove the sulfuric acid from my sample or else my filter paper will not dry. But the major problem is sulfuric acid takes longer time to dry. It could takes even month. I've tried leave it for a month and it still wet. My lecturer asks me to rinse my sample + filter paper with cold water (distilled water). And when I did my sample which is the precipitate is LESS. Maybe because I used large amount of cold water. Is there are suggestions or methods to remove the sulfuric acid?
Sulfuric acid is an excellent dessicant and is also very non-volatile itself (it boils at 337 °C). In other words it would likely still have been there in yet another month.
Your instructor was correct to suggest that you rinse the sulfuric acid with some cold water. Benzoic acid does have some non-negligible solubility in water (1.7 g/L at 0 °C). Unfortunately, it is even more soluble in most organic solvents so cold water may well be your best bet. The solubility in 25 °C water is 3.4 g/L, twice the solubility that it has at 0 °C, so definitely keep it cold.
Additionally, use as little water as necessary to get the sulfuric acid out. If you are working with a gram or so of benzoic acid, I would start with a dropwise addition of about 10 mL. If it’s still gooey, or still appears wet the next day, you need to repeat the rinse. It’s best if you can use a vaccum filter system of course, and spread the material thin and even before rinsing.