Question

Which of the following would lead to higher yields of pure products? Explain why or why not for each.

a) Try to form crystals as fast as possible.

b) Try to form crystals as slowly as possible.

c) Use hot solvent to rinse crystals in Buchner funnel.

d) Use cold solvent to rinse crystals in Buchner funnel.

e) Use a mixed solvent of two immiscible liquids.

f) Use a mixed solvent of two miscible liquids.

g) Use enough solvent to dissolve the compound when hot, so that some liquid remains for filtering.

h) Make sure that no liquid remains when filtering is initiated.

Answer 1

The following steps will lead to yield pure and higher product

(b) Try to form crystals as slowly as possible. If crystals are made fast, srystalization will not be effective, we may end up with impure crystals.

(d) Use cold solvent to rinse crystals in Buchner funnel. Hot solvent may dissolve the crystals.

(f) Use a mixed solvent of two miscible liquids. Solvents must be miscible. If solvents are imiscible the compound may not be exposed to the imiscible solvent.

(g) Use enough solvent to dissolve the compound when hot, so that some liquid remains for filtering