FINAL ORG CHEM

What is the best description of the covalent bonds?

What is the best description of the covalent bonds?

Results from the sharing of electrons between two nuclei

What is the best description of resonance structures?

Structures having the same placement of atoms but different arrangement of electrons

Rank the bond length and bond strength among three types of following carbon hybridization: sp, sp2, and sp3.

Increasing bond length and decreasing bond strength

Which information can you have from Lewis structure?

All of these statements

Give carbon hybridization having an orbital with 33% s-character

sp2

Give the number of lone pairs in Lewis structure of urea, CO(NH2)2

5

Give the number of resonance structures for this resonance hybrid

5

Rank three molecules H2C=O, BF3, and NH3 by increasing their polarity

BF3 < H2C=O  <  NH3

Give molecular shape of amonia (NH3)

Trigonal pyramid

What types of orbital do the lone pairs on oxygene reside in a H2C=O molecule

each in a sp2 orbital

What is the best description of the Lewis acid?

A chemical species contains an empty orbital which is capable of accepting an electron pair; an electron pair acceptor

Give a correct favorable formation of acid-base reaction

Reaction favors formation of the weaker acid and base

How do the intermolecular forces relate to boiling point and melting point of an organic substance.

Increasing strength of intermolecular forces, increasing boiling point and melting point

How does pKa  relate  to Ka and acid strength?

The smaller pKa, the larger Ka and the stronger acid

Give a correct statement

The acidity of H-A increases with the presence of electron-withdrawing groups in A

What is the best description on hydrophobic and/or hydrophilic moieties?

Hydrophobic moiety is a nonpolar part of a molecules that is not attracted to water. Hydrophilic moiety is a polar part of a molecules that is attracted to water.

Identify functional groups in each isomer having molecular formular C4H10O

Alcohol or ether

Rank the compounds in order to increase boiling point

(CH3CH2CH2)2O, CH3(CH2)5OH, CH3CH2CH2COOH

Rank the compounds in order to increase acidity

I, III, II

Which of the following hydrogen atom is the most acidic hydrogen

III

What is the best description for the parent chain in alkanes?

A longest carbon chain

Give a correct IUPAC name of bellow compound

2,2,6,6,7-pentamethyloctane

Which is a correct description on physical properties of alkanes

Melting point increases with increased symmetry

Which points are required for numbering carbon atom in the carbon skeleton of alkanes and cycloalkanes

All of these statements

Give a correct IUPAC name of bellow compound

(Cis)-1-sec-butyl-3-methylcyclohexane

Give number of different staggered and eclipsed conformations along C2-C3 of n-butane.

4

Rank following conformations in order to increase of stability

IV, II, I, III

Rank the compounds in order to increase melting point

CH3CH(CH3)CH2CH2CH2CH2CH3, CH3(CH2)6CH3, (CH3)3CC(CH3)3

Which statement is incorrect on reaction of alkyl halides

Alkyl halides undergo elimination reactions with Lewis acids

Give number of possible isomers formed by dehydrohalogenation of 2-bromo-4-methylpentane

3

Which information can you have from degree of unsaturation (index of hydrogen deficiency)

Number of π-bonds and rings in a molecule

Give a correct IUPAC name of bellow compound

6-ethyl-1-methylcyclohexene

Which is correct description on physical properties of alkenes

Cis-isomer is more polar than Trans-isomer

Identify degree of unsaturation in a compound with molecular formula C9H6O3

7

Give correct geometric isomers of below compounds

I-Cis and II-E

Give numbers of constitutional isomers of alkyne having molecular formula C6H10

7

Which statement is correct on chemical properties of alkenes and alkynes

Alkenes and ankynes easily involve addition reactions

Give major product of reaction between terminal alkynes with 1 equivalent of hydrogen halide

An alkenyl halide that H atom bond to the terminal carbon

Give major product of Markovnikov addition of water to alkynes except acetylene

A kenone

Give major product(s) of bellow reactions

Cyclohexene

Which statement is correct about alcohols.

Alcohols are organic compounds that carry at least one hydroxyl group bound to a saturated carbon atom.

Give a compound that has anaesthetic property

Diethyl ether

Which compound is synthesized through an intramolecular SN2 reaction

An epoxide

Which statement is incorrect about epoxides.

Epoxides are capable of intermolecular hydrogen bonding

Rank capable of intermolecular hydrogen bonding and steric hindrance among primary, secondary and tertiary alcohols

Decreasing ability to hydrogen bonding and increasing steric hindrance

Which statement is correct about general reactions of alcohols, ethers, and epoxides.

Nucleophilic groups react with epoxides but do not react with neither alcohols nor ethers

Which statement is incorrect for structure of benzene

Benzene has alternating single and double bonds

Prefixes ‘ortho’ and ‘meta’ are used to name benzene derivatives with following numbers

1,2-disubtitutions and 1,3-disubtitutions

Give a correct IUPAC name for bellow compound

3-ethoxy-4-ethyltoluene

Which of following names are groups

benzyl and phenyl

Which statement is incorrect in nomenclature of polysubstituted benzene derivatives

substituents are placed with numbers of the following prefixes ortho, meta, and para

Give the best description of a aromatic compound

all of these statements

Compare stability of following molecules

(I) is more stable than (II), (IV) is more stable than (III)

Which molecule is an aromatic compound

Cycloheptatrienyl cation

Give numbers of π electrons in this molecule

10

Give the most acidic hydrogen atom among bellow molecules

cyclopentadiene

Which statement is incorrect on structure of aldehydes, ketones, and carbonyl group

The carbonyl group is strong electron donating group

Which statement is correct on the tautomerism and tautomers

Contitutional isomers are tautomers

Give a method to synthesize aldehydes

Hydroboration-oxidation of terminal alkyne

Which statement is incorrect on nomenclature of aldehydes and ketones

The main chain is the longest continuous chain of carbon atoms

Which statement is incorrect on physic properties of aldehydes and ketones

Aldehydes and ketones are capable of intermolecular hydrogen bonding.

Give possible products of the oxidative cleavage of an alkene by ozonolysis reaction

all of these products

Which is incorrect general feature-reactions of aldehydes and ketones

Reaction of carbonyl group with a Bronsted or Lewis base

Which of the following reactions give a proposed product

III

What alkene yields acetone and formaldehyde after treatment with ozone followed by CH3SCH3

2-methylpropene

Give numbers of constitutional isomers of C8H12 which undergoes the oxidative cleavage of alkenes to give only 3-oxobutanal (CH3COCH2CHO).

2

What group in order of decreasing reactivity in nucleophilic acyl substitution?

CF3CO)2O, (CH3CH2CO)2O, CH3CH2COOCH2CH2CH3

What group in order of increasing boiling point?

A.(CH3CH2CH2)2O, CH3(CH2)5OH CH3CH2CH2CH2COOH

Rank the compounds in each group in order of increasing acidity

I

Give the reaction sequence.

IV

Propanoic acid could be formed when 1-propanol reacts with:

Potassium dichromate (K2Cr2O7) in aqueous sulfuric acid, heat

Which of the following reactions would NOT produce a carboxylic acid?

A.CH3CH2CH2OH+PCC→?

Give reaction

II

Choose group of the compounds in order of decreasing acidity:

Propanedioic acid, propanoic acid, 1,3-propanediol

Isoleucine is an α-amino acid that is essential in humans, meaning the body cannot synthesize it, and must be ingested in our diet. The absolute configuration of isoleucine is 2S,3S. Give the structure of isoleucine?

II

There are various methods that can be used for the preparation of Carboxylic acids.

All mentioned methods are corrected.

Propanoic acid could be formed when 1-propanol reacts with:

Potassium dichromate (K2Cr2O7) in aqueous sulfuric acid, heat

Which of the following should be the most volatile?

CH3CH2CH2CH3

When excess of ethyl iodie is treated with ammonia, the product is:

Tetraethylamimoniu iodide

Benzoic acid is treated with SOCl2 and the product X formed is reacted with ammonia to give Y. Y in the reaction is

benzamide (C6H5CONH2)

The most basic compound among the following is

I

Arrange the following compounds in increasing order of basicity?

C6H5NH2 < NH3 < CH3NH2 < (CH3)2NH

Give reaction sequent:

CH3CH2CH2CONHCOCH3

Five- and six-membered ring structures are common in carbohydrates and are often in equilibrium with each other. The five-membered ring structures are called furanose forms; the six-membered ring structures are pyranose forms. D-Ribose, especially in its β-furanose form, is a familiar carbohydrate,

The β-furanose and β-pyranose forms of D-ribose are:

Which of the following sugars has the configuration (2S, 3R, 4R)?

C

The carbohydrate shown here is a component of a drug used in veterinary medicine. Which is its most stable pyranose conformation?

B

Which of the structures 1 through 4 is methyl α-D-galactopyranoside?

C

Give mechanism of ether cleavage reaction

Both SN1 and SN2

Give a correct statement on the ring opening reaction of epoxides

Reaction gives a final product containing at least an alcohol functional group

The 2,2-dimethylcyclopentanol underwent dehydration in sulfuric acid to form alkenes. Give the best description for the product(s)

II, III, and IV