extraction

Question 1

In this experiment, you will be using both an acid solution and a base solution. To extract an acid from a mixture into an aqueous solution and then recover it from the aqueous solution-

A. You will add an acid solution in the first part to extract and then use base to recover the acid.

B. You will add a base solution in the first part to extract and then use acid to recover the acid.

Answer 1

B. You will add a base solution in the first part to extract and then use acid to recover the acid.

Question 2

True or false? During the extraction process when you have both organic and aqueous solutions in immiscible layers, the naphthalene will be in the organic layer.
True
False

Answer 2

True

Question 3

How will you recover the naphthalene from its solution at the end of the extraction?
By adding an acid to the solution
Filter the product
Evaporate the solvent
By adding water to the solution

Answer 3

Evaporate the solvent

Question 4

True or False? During the extraction procedure, the organic layer will be on the top layer.
True
false

Answer 4

true

Question 5

In your extraction, the organic layer will mainly be the organic solvent. What organic solvent will you use?
Dichloromethane
Sodium hydroxide
Diethyl ether
Chloroform

Answer 5

Diethyl ether

Question 6

Benzoic acid (an organic acid) is soluble in which of the following organic solvents?

Diethyl ether
Water
Sodium hydroxide (NaOH 6M)
All of the above!

Answer 6

Diethyl ether

Question 6

Benzoic acid (an organic acid) is soluble in which of the following organic solvents?

Diethyl ether
Water
Sodium hydroxide (NaOH 6M)
All of the above!

Answer 6

Diethyl ether

Question 7

what is the equation for percent recover

Answer 7

(combined weight of the isolated compounds/weight of the starting mixture) x 100

Question 8

Your recovery is highly unlikely to be exactly 100%. Which of the following are possible reasons why your recovery is less than 100%?

Mechanical losses (e.g. during transfers)
Incomplete deprotonation
Incomplete reprotonation
All of the above are possible reasons!

Answer 8

All of the above are possible reasons!

Question 9

Suppose, after extraction, you did not allow enough time for the recovered benzoic acid to dry. Therefore, it was still wet when you measured its weight and calculated the percent recovery. Which of the following do you think might be your value for percent recovery?

<100%
>100%
Cannot be determined. Need more information.

Answer 9

> 100%

Question 10

Suppose, the melting point of a certain compound is observed to be have a narrow range (1-3 oC) and matches to the literature range for that compound.

What will be your conclusion about the purity of the compound?

Pure
Impure

Answer 10

pure

Question 11

what is the polarity of carbon tetrachloride

Answer 11

non polar

Question 12

what is the polarity of water

Answer 12

polar protic

Question 13

what is the polarity of diethyl either

Answer 13

polar aprotic

Question 14

what is the polarity of acetone

Answer 14

polar aprotic

unable to form hydrogen bonds a

Question 15

what is the polarity of methanol

Answer 15

polar protic

polar solvents that have at least 1 hydrogen that is connected directly to a particular electronegative atom such as O-H, N-H,,

Question 16

What are the TWO most important IMFs between sodium sulfate and water

Answer 16

ion-dipole forces and hydrogen bonding

Question 17

After extraction of the benzoic acid into the aqueous solution as its anionic salt, the ether solution was then washed with water two further times. What do you think was the purpose of these two wash steps?
To remove any remaining sodium hydroxide from the ether
To remove any remaining benzoic acid salt from the ether
To remove any remaining polar impurities from the ether
All of the above

Answer 17

All of the above

Question 18

The ionized benzoic acid dissolves better in water than it does in diethyl ether, which is how and why it is extracted into the water phase. Give the TWO most important IMFs that are responsible for solubilizing the benzoic acid anion in the water

Answer 18

ion dipole forces and hydrogen bonding

Question 19

As a follow-up to the previous question, give also the most important IMF that is responsible for solubilizing the sodium cation in the water.

Answer 19

ion dipole bonding