PART A: (T/F) While not all stereoselective reactions are stereospecific, stereo

Question

PART A: (T/F) While not all stereoselective reactions are stereospecific, stereospecific reactions are always stereoselective.

TRUE

FALSE

Bromoethane reacts with sodium ethoxide utilizing ethanol as a solvent produces diethyl ether.

PART B: How is iron chloride stain made and why is it selective to phenols when developing TLC plates? A. 50mL of water is combined with 50mL of methanol and 1 gram of ferric (III) chloride; Iron Chloride acts as a Lewis acid and phenols, which are acidic with a pka of ~10, act as the Lewis base. The color is a result of the interaction of up to three phenol molecules donating their non-bonding electrons to a single iron acting as a Lewis acid and accepting the non-bonding electrons. B. 50mL of water is combined with 50mL of methanol and 1 gram of ferric (III) chloride; Phenols are acidic (with a pka of ~10) and donate protons to the chloride atoms from the iron making hydrochloric acid. The phenol anion then reacts with the methanol to methyoxybenzene also known as anisole. The anisole decomposes under heat leading to the color seen on the TLC plate. C. 1% FeCl2 is combined with 50% aqueous methanol, the reaction on the TLC plate is the result of the decomposition of the product containing an ionic bond between the negatively charged phenolate and the positively charged chlorine as this is the product when phenol reacts with FeCl2 in the presence of silica and methanol. D. No answer text provided. PART D: Discovered in 1850's, this reaction undergoes what type of mechanism?

Bromoethane reacts with sodium ethoxide utilizing ethanol as a solvent produces diethyl ether.

A. Sn2 B. Sn1 C. E1 D. E2

Explanation / Answer

Part A) while not all stereoselective reactions are stereospecific, stereospecific reactions are always stereoselective.

Answer: False

Explanation

Stereospecific reactions produce only one stereoisomer exclusively whereas, stereoselective reactions produce both stereoisomers. Here, one stereoisomer is preferred over the other.

Part B) how is iron chloride stain made and why is it selective to phenols when developing TLC plates?

Answer: 50 mL of water is combined with 50mL of methanol and 1 gram of ferric (III) chloride; Iron Chloride acts as a Lewis acid and phenols, which are acidic with a pka of ~10, act as the Lewis base. The color is a result of the interaction of up to three phenol molecules donating their non-bonding electrons to a single iron acting as a Lewis acid and accepting the non-bonding electrons.

Explanation

Ferric ion is hard acid according to the HSAB theory. It will selectively react with the phenolic oxygen (Hard base). This reaction will not happen if ferrous ions (borderline acid) are used

Part D) Discovered in 1850's, this reaction undergoes what type of mechanism?

Bromoethane reacts with sodium ethoxide utilizing ethanol as a solvent produces diethyl ether.

Answer: Sn2

Explanation

Primary substrate and strong nucleophile favor Sn2 mechanism. Here, Bromoethane is a primary substrate and sodium ethoxide is a strong nucleophile

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