Question

1.

a)Calculate the percent recovery if a recrystallization procedure yields 2.50 mg of pure product from 4.15 mg of crude product.

b)A crude mixture of compound A (desired product, MP = 80°C) with compound B (impurity, MP = 84°C) is separated by recrystallization. What is the expected melting point in each of the following experiments? (2 pts)

Recrystallized “A” with Pure “A” (choose one)
(a) 80°C (b) 82°C (c) 84°C (d) less than 80°C (e) greater than 84°C

Recrystallized “A” with Pure “B” (choose one)
(a) 80°C (b) 82°C (c) 84°C (d) less than 80°C (e) greater than 84°C

Answer 1

1) yield=out put (2.5) /in put(4.15)

=60.24℅

2) if re recrystallized A with pure A then melting point

Is 80 degrees

because both are compound A so melting point can not change.

3) if Recrystalized A with pure B then melting point is less than 80 degrees

Because compound A+B mixed so different melting point compound s mixture Will decrease the original melting point

Thank you.