Alkyl Halides Lecture Notes

Flashcards covering the properties, reactions, and mechanisms of alkyl halides based on MCQ lecture notes.

Which reagent is known as a "synthetic tool in the hand of a chemist"?

Grignard’s reagent

In which solvent are the reactions of Grignard’s reagents generally carried out?

Ether

What is produced by the reaction of ethyl chloride with alcoholic $KOH$?

Ethene

What is a reaction called in which an atom or group is replaced by another atom or group?

Substitution

What is produced when carbon dioxide is passed through $R-Mg-X$?

Any carboxylic acid except formic acid

What is produced by the reaction of Grignard’s reagent with ammonia?

Alkanes

What is the best way to obtain alkanes from the Grignard’s reagent?

Reacting with water

What type of alcohol is obtained by reacting Grignard’s reagent with formaldehyde ($HCHO$)?

$1^\text{o}$—alcohol

What type of compound is Grignard’s reagent?

An organometallic compound

Is the transition state formed in an $S_N1$ or $S_N2$ reaction?

$$S_N2$$

How many steps are involved in an $S_N2$ reaction?

It is a uni-step (one step) reaction

Which type of alkyl halide generally undergoes $S_N1$ reactions?

$$3^\text{o}R-X$$

Which site of a molecule does a nucleophile generally attack?

An electron deficient site

What is the name of the reaction: Ethyl bromide + ammonia $\rightarrow$ Ethyl amine + $HBr$?

Ammonolysis

What is the elimination of hydrogen and halogen from two adjacent carbon atoms called?

Dehydrohalogenation

Which metal is used in Wurtz’s reaction?

Sodium ($Na$)

What is the chemical formula for thionyl chloride?

$$SOCl_2$$

What are monohalo derivatives of alkanes called?

Alkyl halides

What product is formed when Grignard’s reagent reacts with acetone?

$3^\text{o}$—alcohol

Which alkyl halide is more reactive: $R-I$, $R-Br$, or $R-Cl$?

$$R-I$$

What is the rate-determining step in an $S_N1$ reaction?

The formation of the carbonium ion

What is the order of stability for alkyl halides?

$$3^\text{o} > 2^\text{o} > 1^\text{o}$$

What is the general formula for alkyl halides?

$$C_nH_{2n+1}X$$

Which type of alkyl halide can show both $E_1$ and $E_2$ mechanisms?

$$2^\text{o}-RX$$

Primary alkyl halides generally follow which elimination mechanism?

$E_2$ mechanism

Elimination reactions are usually catalyzed by what?

Base

In the context of $R-X$, what can the "$R$" group NOT be?

Aromatic

What is the alkyl halide molecule on which a nucleophile attacks called?

Substrate

What charges can a nucleophile have?

Negative or Neutral

What charges can an electrophile have?

Positive or Neutral

Which halogen is both a nucleophile and a good leaving group?

Iodine ($I$)

What is the major factor determining the reactivity of an alkyl halide?

Bond energy

How does the reactivity of an alkyl halide change as the size of the halogen atom increases?

Reactivity increases

Among the carbon-halogen bonds, which one is most stable?

$$C-F$$

Which nucleophile attacks an alkyl halide to form thio-alcohol?

$$SH^-$$

On which specific alkyl halide does $\beta$-elimination not occur?

Neo-pentyl chloride

Which reagent can convert an alkyl halide to alcohol?

$$KOH_{\text{(aq)}}$$

In which type of solvents are alkyl halides soluble?

Polar solvents

Which type of alkyl halide increases the rate of an $S_N2$ reaction?

Primary alkyl halide

Which type of halide undergoes an $S_N1$ reaction most readily?

$3^\text{o}$ alkyl halide

What is the product of the reaction between an alkyl halide and alcoholic $KOH$?

Alkene

What type of bond exists between carbon and halogen in alkyl halides?

Polar covalent

What is the correct decreasing order of reactivity for alkyl halides in an $S_N2$ reaction?

$$RI > RBr > RCl$$