GOC Flashcards
The p-isomer of dichlorobenzene has higher melting point than o- and m-isomer. Why?
The melting point of para isomer is quite higher than that of ortho or meta isomers. This is due to the fact that it has symmetrical structure and therefore, its molecules can easily pack closely in crystal lattice. As a result intermolecular forces of attraction are stronger and therefore, greater energy is required to break its lattice and it melts at higher temperature.
What are enantiomers?
Stereoisomers which are non superimposible mirror images of each other are called enantiomers.
Which will have a higher boiling point: 1-chloroethane or 2-methyl-2-chlorobutane ? Give reasons.
2-Methyl-2-chlorobutane has higher boiling point than 1-chlorobutane because with increase in size of alkyl group, boiling point increases.
Optically active isomers
The number of optically active isomers is equivalent to 2^n.
Which one of the following conformations of cyclohexane is chiral?
Boat
Twist Boat
Chair
None of the above
A twist boat conformation of cyclohexane is chiral.
How many chain isomers does butylene have?
A butylene molecule has two chain isomers: n-butane and isobutylene.
What is a racemic mixture?
A racemic mixture is the homogenous mixture of two enantiomers in a comparable amount. A racemic mixture shows different properties from enantiomers.
Optical isomerism is a type of _________
stereoisomerism
The d-form is also known as ______
dextrorotatory
define d-form and l-form isomers
The isomer which rotates the plane of polarized light towards the right that is clockwise, is known as a dextrorotatory or d form while that which rotates towards the left that is anti-clockwise, is known as laevorotatory or l-form.
How many planes of symmetry does a meso compound have?
The compound whose half part of a molecule is a mirror image of the other half, is called meso form. Generally, a meso compound has two or more chiral centers and one plane of symmetry. the compound in meso form is optically inactive due to internal compensation.
Acetaldehyde and ethenol show _____
The compounds acetaldehyde and ethenol exhibit tautomerism. Tautomerism is a special type of functional isomerism which arises in carbonyl compounds containing α-hydrogen atom, it is a change of keto form to enol form.
What is the other name for acyclic compounds?
Aliphatic
Which of these is not an aliphatic compound?
a) Acetic acid
b) Acetaldehyde
c) Ethane
d) Tetrahydrofuran
d) Tetrahydrofuran
Tetrahydrofuran is a closed chain or a ring compound. Acetic acid, acetaldehyde, and ethane are open chain compounds, thereby, making them aliphatic compounds. Tetrahydrofuran is an organic compound with the formula (CH2)4O.
Identify the condensed formula of ethane from the following.
a) CH3-CH3
b) HC-H2-C-H3
c) CH2=CH2
d) CH3CH3
d
In condensed formula, all the atoms are represented but single bonds are not shown.
