Hydration of Noroborene

Why is sulfuric acid used as a catalyst instead of hydrochloric acid in this hydration?

HCl contains a chloride ion that is a strong nucleophile and would compete with water to form an alkyl halide; the conjugate base of H2SO4 is a poor nucleophile and does not compete.

What is the primary safety hazard associated with concentrated sulfuric acid?

It is extremely acidic and corrosive; it can cause severe chemical burns upon contact with skin.

Why should acetone never be used to clean glassware that contains bromine residues?

Acetone reacts with bromine to form bromoacetone, which is a powerful lachrymator (tear gas).

How should brown manganese dioxide (MnO2) stains be removed from glassware?

They can be rinsed with a 30% aqueous solution of sodium bisulfite (NaHSO_3).

What are the three main steps in the acid-catalyzed hydration mechanism shown in the notes?

1. The alkene acts as a nucleophile to attack H+ (protonation); 2. Water acts as a nucleophile to attack the resulting carbocation; 3. Loss of a proton to yield the alcohol.

Why are addition reactions of alkenes generally exothermic?

A weaker pi-bond is broken and replaced by two stronger sigma-bonds, which releases energy.

What is Markovnikov’s Rule as applied to unsymmetrical alkenes?

The electrophile adds to the carbon that results in the formation of the more stable carbocation intermediate.

Describe the difference between "syn-addition" and "anti-addition."

Anti-addition involves reagents adding to opposite faces of the double bond, while syn-addition involves reagents adding to the same face.

Why does the hydration of norbornene yield exo-norborneol instead of endo-norborneol?

Steric hindrance from atoms on the underside of the bridged ring blocks "endo" attack; the "exo" face is more accessible.

What visual change occurs during a positive Baeyer Test (KMnO4) for unsaturation?

The purple color of the permanganate disappears and a brown precipitate of MnO2 forms.

What do the numbers in a standard-taper joint (e.g., 14/20) represent?

The first number is the diameter of the joint at its widest point (mm), and the second is the length of the joint (mm).

What is the purpose of greasing ground-glass joints?

To create an airtight seal and prevent the joints from "freezing" (becoming stuck) together.

Define the process of sublimation used in this experiment.

Sublimation is a separation technique where a substance transitions directly from a solid phase to a gaseous phase.

How can you prevent losing your product via sublimation after the reaction is complete?

Place the product in a petri dish, cover it with a lid, and wrap the edges with parafilm to trap the vapor.

If the literature yield is 65% but you obtain 30%, what are likely causes for this discrepancy?

Common causes include incomplete reaction, loss of product during transfer, or loss due to unintended sublimation if the container wasn't sealed.

What does a melting point range that is lower and broader than the literature value indicate?

It indicates that the sample is impure or contains residual solvent.

How can IR spectroscopy distinguish between the starting material (norbornene) and the product (exo-norborneol)?

The product will show a broad -OH stretch (alcohol) and the disappearance of the alkene C=C stretch found in the starting material.

Why is the "fingerprint region" of the IR spectrum necessary to confirm the synthesis of exo-norborneol?

While the functional group region shows that an alcohol was formed, the fingerprint region provides a unique "ID" to confirm it is the specific exo