Orgo 1 Lab Final Review

B. Thin Layer Chromatography

TLC stands for…

A. Tender Love & Care

B. Thin Layer Chromatography

C. Thick Layer Chromatography

D. Thin Liquid Chromatography

A. polarity

In TLC, substances are separated because of differences in _____. Check all that apply.

A. polarity

B. concentration

C. molecular size

D. electronegativity

A. True

The distance travelled by the compound depends on how soluble it is in the chosen solvent.

A. True

B. False

If the eluent level is above the baseline on the TLC plate, it can prevent the samples from migrating properly and dissolve them within the pool of solvent. The samples may also mix, leading to improper separation of sample components.

When pouring your eluent into the TLC developing chamber, you should ensure that the eluent level is below the baseline on your TLC plate. Why?

A. To identify the proper S_N1 and S_N2 mechanisms on 6 different types of alkyl halides and to identify the order of reactivity of each.

What is the purpose of the experiment (nucleophilic substitution reactions I - Mechanisms and synthesis)?

A. To identify the proper S_N1 and S_N2 mechanisms on 6 different types of alkyl halides and to identify the order of reactivity of each.

B. To synthesize 6 different types of alkyl halides and measure their boiling points.

C. To determine the solubility of 6 different types of alkyl halides in various solvents.

D. To observe the reaction of 6 different types of alkyl halides with ethanolic silver nitrate solution.

B. The reaction proceeds via two steps

Which statement is incorrect about the reaction of 1-bromobutane and hydroxide ion?

A. The leaving group is Br^-

B. The reaction proceeds via two steps

C. The reaction is accompanied by inversion of configuration

D. The kinetic rate involves both reactants

D. HO^-

Which of the following group is not a good leaving group?

A. Br^-

B. TsO^-

C. I^-

D. HO^-

D. (CH₃)₃CBr

Which of the following is least likely to undergo an S_N2 reaction?

A. CH₃Br

B. CH₃CH₂Br

C. (CH₃)₂CHBr

D. (CH₃)₃CBr

B. R=K[R-X][Nuc]

What is the rate law of an S_N2 reaction?

A. R=K[R-X]

B. R=K[R-X][Nuc]

C. R=K[R-X]/[Nuc]

D. R=K[Nuc]

C. Tert-butyl chloride

Which of the following alkyl halides undergoes fastest S_N1 reaction?

A. Methyl iodide

B. Ethyl bromide

C. Tert-butyl chloride

D. Isopropyl fluoride

A. Br^-

Which of the following is a good leaving group?

A. Br^-

B. CH₃

C. H⁺

D. NH₂

C. Racemic mixture

What is the stereochemistry of product formed in an S_N1 reaction?

A. Retention of configuration

B. Inversion of configuration

C. Racemic mixture

D. No change in configuration

CH₃Br + NaOH ——> CH₃OH + NaBr

Write a balanced chemical equation for the reaction between methyl bromide and sodium hydroxide.

C. C has a partial negative; Mg has a partial positive charge

Which of the following describes the bond between C and Mg in the Grignard reagent?

A. Nonpolar

B. Mg has partial negative; C has a partial positive charge

C. C has a partial negative; Mg has a partial positive charge

D. No bond between Mg and C

B. Biphenyl

What is the side product of Grignard synthesis of benzoic acid?

A. Dimethylphenyl

B. Biphenyl

C. Phenylether

D. Magnesiumether

Acidify the solution leading to the precipitation of benzoic acid from sodium benzoate.

The role of HCl in the extraction of benzoic acid from side product is to ____.

A. R

Given a Grignard reagent RMgX, the nucleophile is

A. R

B. X

C. RX

D. MgX

C₆H₅COONa + HCl —————> C₆H₅COOH + NaCl

Write an equation for the reaction between sodium benzoate and hydrochloric acid.

Successive extraction is when several rounds of solvent are added to a sample to separate the components of the sample into different layers. These several rounds of solvent are done individually and apart from one another, ensuring that the entire procedure for a normal extraction is done each time before adding another batch of solvent in.

What is successive extraction?

Anhydrous magnesium sulfate and anhydrous sodium sulfate

Give two examples of drying agents used in purification of organic solution.

The water is the bottom layer and the toluene is the top layer.

The image below shows separation of toluene and water of density 0.867 g cm^-3 and 0.997 g cm^-3 respectively. Identify which is top and bottom layer?

C₇H₅NaO₂ + HCl ——> C₇H₅O₂H + NaCl

Write an equation to show the product formed on reaction sodium benzoate with hydrochloric acid.

Polar: Water, methanol

Non-polar: Hexane, toluene

Give one example each of polar and non-polar compounds.

B. Filtration

Insoluble solids are separated from a mixture by _____.

A. Crystallization

B. Filtration

C. Chromatography

D. Boiling

C. Solubility

The physical property of compounds exploited in crystallization is _____.

A. Melting point

B. Boiling point

C. Solubility

D. Bond strength

Melting point, freezing point, boiling point, refractive index….

Give one physical property that can be used to check for purity.