DP Chemistry Questionbank

Construct the mechanism of the formation of 2-bromopropane from hydrogen bromide and propene using curly arrows to denote the movement of electrons.

When the product X is reacted with NaOH in a hot alcoholic solution, C₂H₃Cl is formed. State the role of the reactant NaOH other than as a nucleophile.

State the reagents used to convert benzene to nitrobenzene and the formula of the electrophile formed.

State the reagents used in the two-stage conversion of nitrobenzene to aniline.

In which order should the reagents be used to convert benzene into phenylamine (aniline)?

State the reagents and the name of the mechanism for the nitration of benzene.

Below are two isomers, A and B, with the molecular formula C₄H₉Br.

Explain the mechanism of the nucleophilic substitution reaction with NaOH(aq) for the isomer that reacts almost exclusively by an S_N2 mechanism using curly arrows to represent the movement of electron pairs.

State the reagents used in the nitration of benzene.

State an equation for the formation of NO₂⁺.

Explain the mechanism of the reaction between 2-bromo-2-methylpropane, (CH₃)₃CBr, and aqueous sodium hydroxide, NaOH (aq), using curly arrows to represent the movement of electron pairs.

Compare and contrast the mechanisms by which 1-chlorobutane, CH₃CH₂CH₂CH₂Cl, and 2-chloro-2-methylpropane, (CH₃)₃CCl, react with aqueous sodium hydroxide, giving two similarities and one difference.

Outline why the rate of reaction of the similar bromo-compounds is faster.

Suggest how this product could be synthesized in one step from butanoic acid.

Propene is reacted first with hydrogen chloride to produce X which is then reacted with aqueous sodium hydroxide to give Y. Finally, Y is reacted with excess acidified potassium dichromate solution.

$$\text{C}{\text{H}}_{\text{3}}\text{CHC}{\text{H}}_{\text{2}}\stackrel{\text{HCL}}{\to }\text{X}\stackrel{\text{NaOH(aq)}}{\to }\text{Y}\stackrel{{\text{H}}^{+}/\text{C}{\text{r}}_2{{\text{O}}_7}^{2-}\text{(aq)}}{\to }\text{Z}$$

What is the major product, Z? 

A.     CH₃CH(OH)CH₃

B.     CH₃COCH₃

C.     CH₃CH₂CHO

D.     CH₃(CH₂)₂COOH

State the type of bond fission that takes place in a S_N1 reaction.

State the type of solvent most suitable for the reaction.

Draw the structure of the intermediate formed stating its shape.

Nitrobenzene, C₆H₅NO₂, can be converted to phenylamine via a two-stage reaction.

In the first stage, nitrobenzene is reduced with tin in an acidic solution to form an intermediate ion and tin(II) ions. In the second stage, the intermediate ion is converted to phenylamine in the presence of hydroxide ions.

Formulate the equation for each stage of the reaction.

Deduce the product of the complete reduction reaction in (e)(i).

Write the equation for the production of the active nitrating agent from concentrated sulfuric and nitric acids.

Explain the mechanism for the nitration of benzene, using curly arrows to indicate the movement of electron pairs.

State the reagent used to convert benzoic acid to phenylmethanol (benzyl alcohol), C₆H₅CH₂OH.

The benzene ring of phenylethene reacts with the nitronium ion, NO₂⁺, and the C=C double bond reacts with hydrogen bromide, HBr.

Compare and contrast these two reactions in terms of their reaction mechanisms.

Similarity: 

Difference:

Which is a major product of the electrophilic addition of hydrogen chloride to propene?

A. ClCH₂CH=CH₂

B. CH₃CH(Cl)CH₃

C. CH₃CH₂CH₂Cl

D. CH₃CH=CHCl

Which class of compound is formed when a ketone is reduced?

A. primary alcohol

B. secondary alcohol

C. ether

D. carboxylic acid

Write an equation for the reaction of the major product with aqueous sodium hydroxide to produce a C₃H₈O compound, showing structural formulas.

Sketch the mechanism using curly arrows to represent the movement of electrons.

In which compound is the halogen substituted the most rapidly by aqueous hydroxide ions?

A. (CH₃)₃CCl

B. (CH₃)₃CI

C. CH₃CH₂CH₂CH₂Cl

D. CH₃CH₂CH₂CH₂I

Which is the electrophile in the nitration of benzene?

A.  ${\mathrm{HNO}}_3$

B.  ${{\mathrm{NO}}_2}^{+}$

C.  ${{\mathrm{NO}}_2}^{-}$

D.  ${{\mathrm{NH}}_4}^{+}$

What will be the major product in the reaction between but-1-ene and $\mathrm{Hbr}$?

A.  2-bromobut-1-ene

B.  1-bromobut-1-ene

C.  2-bromobutane

D.  1-bromobutane

Explain the mechanism of the reaction between chloroethane and aqueous sodium hydroxide, $\mathrm{NaOH} \left(\mathrm{aq}\right)$, using curly arrows to represent the movement of electron pairs.

Which is most likely to hydrolyse via a S_N1 mechanism?

A.  CH₃CHBrCH₂CH₃

B.  (CH₃)₂CHBr

C.  (CH₃)₃CBr

D.  CH₃CH₂CH₂CH₂Br

Which product is formed when CH₃COCH₂CH₃ is reduced with sodium borohydride?

A.  CH₃CH₂CH₂CHO

B.  CH₃CH₂CH₂CH₂OH

C.  CH₃CH(OH)CH₂CH₃

D.  CH₃CH₂CH₂COOH

Explain why the reaction produces more (CH₃)₃COH than (CH₃)₂CHCH₂OH.

Explain the mechanism of the reaction using curly arrows to represent the movement of electron pairs.

Write an equation for the reaction between the acids to produce the electrophile, NO₂⁺.

Predict, giving a reason, the major product of reaction between but-1-ene and steam.

Explain the mechanism of the reaction between 1-bromopropane, CH₃CH₂CH₂Br, and aqueous sodium hydroxide, NaOH (aq), using curly arrows to represent the movement of electron pairs.

State the reagents used in the two-stage conversion of nitrobenzene to aniline.

In which order should the reagents be used to convert benzene into phenylamine (aniline)?

Propene is reacted first with hydrogen chloride to produce X which is then reacted with aqueous sodium hydroxide to give Y. Finally, Y is reacted with excess acidified potassium dichromate solution.

$$\text{C}{\text{H}}_{\text{3}}\text{CHC}{\text{H}}_{\text{2}}\stackrel{\text{HCL}}{\to }\text{X}\stackrel{\text{NaOH(aq)}}{\to }\text{Y}\stackrel{{\text{H}}^{+}/\text{C}{\text{r}}_2{{\text{O}}_7}^{2-}\text{(aq)}}{\to }\text{Z}$$

What is the major product, Z? 

A.     CH₃CH(OH)CH₃

B.     CH₃COCH₃

C.     CH₃CH₂CHO

D.     CH₃(CH₂)₂COOH

The minor product, C₆H₅–CH₂–CH₂Br, can be directly converted to an intermediate compound, X, which can then be directly converted to the acid C₆H₅–CH₂–COOH.

C₆H₅–CH₂–CH₂Br → X → C₆H₅–CH₂–COOH

Identify X.

Propanone can be synthesized in two steps from propene. Suggest the synthetic route including all the necessary reactants and steps.

Propanone can be synthesized in two steps from propene.

Suggest why propanal is a minor product obtained from the synthetic route in (g)(i).

Sketch the mechanism for the reaction of propene with hydrogen bromide using curly arrows.

Explain why the major organic product is 2-bromopropane and not 1-bromopropane.

Explain why the major organic product is 2-bromopropane and not 1-bromopropane.

Vision is dependent on retinol (vitamin A) present in retina cells. Retinol is oxidized to the photosensitive chemical 11-cis-retinal and isomerizes to 11-trans-retinal on absorption of light.

Outline how the formation of 11-trans-retinal results in the generation of nerve signals to the brain.

Describe what happens to plane-polarized light when it passes through a solution of an optically active compound.

A mixture of enantiomers shows optical rotation.

Suggest a conclusion you can draw from this data.

Below are two isomers, A and B, with the molecular formula C₄H₉Br.

Explain the mechanism of the nucleophilic substitution reaction with NaOH(aq) for the isomer that reacts almost exclusively by an S_N2 mechanism using curly arrows to represent the movement of electron pairs.

Which molecule contains a chiral carbon?

A.     CH₃CH₂CHBrCH₂CH₃

B.     CH₃CH₂CHBrCH₃

C.     CH₂BrCH(CH₃)CH₂Br

D.     CH₃CH₂CH₂CH₂CH₂Br

Suggest, giving a reason, the percentage of each isomer from the S_N1 reaction.

Sketch the wedge and dash (3-D) representations of alanine enantiomers.

How many chiral carbon atoms are present in one molecule of (CH₃)₂CHCHClCHBrCH₃?

A.   0

B.   1

C.   2

D.   3

The organic product is not optically active. Discuss whether or not the organic product is a racemic mixture.

Outline why the major product, C₆H₅–CHBr–CH₃, can exist in two forms and state the relationship between these forms.

Two forms: 

Relationship:

The minor product, C₆H₅–CH₂–CH₂Br, can exist in different conformational forms (isomers).

Outline what this means.

Label with an asterisk, *, the chiral carbon atom.

Which can show optical activity?

A.  CHBrCHCl

B.  CH₃CH₂CHBrCH₂CH₃

C.  (CH₃)₂CBrCl

D.  CH₃CH₂CH(CH₃)Br

Which molecule has an enantiomer?

A.  ${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{CH}\left(\mathrm{OH}\right){\mathrm{CH}}_2{\mathrm{CH}}_3$

B.  ${\mathrm{CH}}_2\left(\mathrm{OH}\right){\mathrm{CH}}_2{\mathrm{CH}}_2\mathrm{CH}={\mathrm{CH}}_2$

C.  ${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CH}}_2\mathrm{CH}=\mathrm{CHBr}$

D.  ${\mathrm{CH}}_3{\mathrm{CHBrCH}}_2{\mathrm{CH}}_2{\mathrm{CH}}_3$

Which compound rotates the plane of plane-polarized light?

A.  CH₃C(CH₃)ClCH₃

B.  CH₃CH₂CHClCH₃

C.  CH₃C(Cl)₂CH₃

D.  CH₃CClBrCH₃

Identify the isomer of Compound B that exists as optical isomers (enantiomers).

Draw the full structural formula of (Z)-but-2-ene.