What effect does branching of an alkane chain has on its boiling point?

What effect does branching of an alkane chain has on its boiling point?
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Ans. As branching increases, the surface area of the molecule decreases which results in a small area of contact. As a result, the Van der Waals force also decreases which can be overcome at a relatively lower temperature. Hence, the boiling point of an alkane chain decreases with an increase in branching.
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Related questions

(a) What effect the branching of an alkane has on its melting point? (L-III) (b) Which of the following has highest boiling point?(L-III) (1) 2-methyl pentane. (2) 2, 3-diethyl butane. (3) 2, 2- dimethyl butane.

Description : (a) What effect the branching of an alkane has on its melting point? (L-III) (b) Which of the following has highest boiling point?(L-III) (1) 2-methyl pentane. (2) 2, 3-diethyl butane. (3) 2, 2- dimethyl butane.

Last Answer : Ans.(a) In general conception, as the branching increases packing of the molecules in the crystals becomes less close and have melting point decreases accordingly. (b) As the branching increases, ... attraction decreases and hence the boiling point decreases. So, 2-methyl pentane has highest B.pt.

What effect does branching of an alkane chain has on its boiling point?

Description : What effect does branching of an alkane chain has on its boiling point?

Last Answer : Ans. As the branching increases, the surface area of an alkane approaches that of a sphere. Since a sphere has minimum surface area, therefore, Vander Waal forces of attraction are minimum and hence the boiling point of the alkane decreases with branching.

Which of the following has highest boiling point and why?(L-II) (a) 2 methylpentane (b) 2,3 dimethyl butane (c) 2,2 dimythylbutane

Description : Which of the following has highest boiling point and why?(L-II) (a) 2 methylpentane (b) 2,3 dimethyl butane (c) 2,2 dimythylbutane

Last Answer : Ans. As the branching increases, surface area decreases. As a result, magnitude of Vander Waals forces of attraction decreases and hence the boiling point decreases. Thus, the overall order of decreasing boiling point is: 2 methylpentane (333k) > 2,3 dimethylbutane (331k) > 2,2 dimethylbutane(323k)

Arrange the three isomers of pentane in increasing order of their boiling points?

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Last Answer : Ans.2, 2-Dimethylpropane

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Out of benzene, m–dinitrobenzene and toluene which will undergo nitration most easily and why?

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Which one is more stable structure of benzene among Kekule and Dewar’s structures?

Description : Which one is more stable structure of benzene among Kekule and Dewar’s structures?

Last Answer : Ans: Kekule’s structure.

Define benzenoids Compounds.

Description : Define benzenoids Compounds.

Last Answer : Ans: Aromatic compounds containing benzene ring.

Define Aromatic Compounds.

Description : Define Aromatic Compounds.

Last Answer : Ans: The Compounds which gives pleasant smell.

What are alkanes? Why are they called paraffins?

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How will you demonstrate that double bonds of benzene are somewhat different from that of olefins?

Description : How will you demonstrate that double bonds of benzene are somewhat different from that of olefins?

Last Answer : Ans. The double bonds of olefins decolorize bromine water and discharge the pink colour of Bayer‘s reagent while those of benzene not.

What is Grignard reagent?

Description : What is Grignard reagent?

Last Answer : Ans. Alkyl magnesium halides

What is meant by restricted rotation around of carbon-carbon double bond? What type of isomerism does it lead to?

Description : What is meant by restricted rotation around of carbon-carbon double bond? What type of isomerism does it lead to?

Last Answer : Ans. The carbon-carbon double bond in alkene contains one sigma bond and one pi-bond. The Pibond involves the overlapping of unhybridised p orbital of two carbon atom .The rotation around the ... , the free rotation around C=C double bond is restricted, which gives rise to Geometrical Isomerism.

How will you detect the presence of unsaturation in an organic compound?

Description : How will you detect the presence of unsaturation in an organic compound?

Last Answer : Ans. Generally Unsaturated organic compound decolorize Bayer‘s reagent and Bromine water.

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Description : Arrange the following in order of decreasing reactivity towards alkanes. HCl, HBr, HI, HF

Last Answer : Ans. HI> HBr> HCl >HF

Name two reagents which can be used to distinguish between ethene and ethyne.

Description : Name two reagents which can be used to distinguish between ethene and ethyne.

Last Answer : Ans. Tollen‘s reagent

Out of ethylene and acetylene which is more acidic and why?

Description : Out of ethylene and acetylene which is more acidic and why?

Last Answer : Ans. Acetylene, due to greater electonegativity of the sp hybridised carbon.

Arrange the following in the increasing order of C-C bond length- C2H6 , C2H4, C2H2

Description : Arrange the following in the increasing order of C-C bond length- C2H6 , C2H4, C2H2

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What are the necessary conditions for any system to be aromatic?

Description : What are the necessary conditions for any system to be aromatic?

Last Answer : Ans. A compound is said to be aromatic if it satisfies the following three conditions: (i) It should have a planar structure. (ii) The π-electrons of the compound are completely delocalized in the ring. (iii)The total number ... to (4n + 2), where n = 0, 1, 2 etc. This is known as Huckel s rule.

Explain why Grignard reagents do not reacts with alkanes.

Description : Explain why Grignard reagents do not reacts with alkanes.

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What are the main constituent of LPG?

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Description : Is it possible to isolate pure staggered ethane or pure eclipsed ethane at room temperature? Explain .

Last Answer : The energy differences between staggered and eclipsed forms of ethane is just 12.55 kj mol_1 which is easily met by collisions of the molecules at room temperature. Therefore, it is not possible to isolate either pure staggered or pure eclipsed ethane at room temperature.

Why do the C-C bonds rather than C-H bonds break during cracking of alkanes?

Description : Why do the C-C bonds rather than C-H bonds break during cracking of alkanes?

Last Answer : Ans. Since the bond dissociation energy of C-C bonds (348kj /mol) is lower than bond dissociation energy of C-H bonds (414kj/mol), therefore, during cracking of alkanes, C-C bonds break more early than C-H bonds.

What do you mean by pyrolysis?

Description : What do you mean by pyrolysis?

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Last Answer : Conformations are spatial arrangements which are obtained by rotation around sigma bonds.

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Which of the following organic compounds is known as a saturated chain hydrocarbon ? w) an aromatic compound x) an alkene y) an alkyne z) an alkane

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How many hydrogens are there in the straight chain alkane that has three carbon atoms?

Description : How many hydrogens are there in the straight chain alkane that has three carbon atoms?

Last Answer : ANSWER: EIGHT

What is the name of the alkane that is composed of a chain of five carbon atoms?

Description : What is the name of the alkane that is composed of a chain of five carbon atoms?

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The branching enzyme acts on the glycogen when the glycogen chain has been lengthened to between glucose units: (A) 1 and 6 (B) 2 and 7 (C) 3 and 9 (D) 6 and 11

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Cellulose, the most important constituent of plant cell wall is made up of (a) branched chain of glucose molecules linked by β-1, 4 glycosidic bond in straight chain and α-1, 6 glycosidic bond at the site of branching (b) unbranched chain of glucose molecules linked by β-1, 4 glycosidic bond (c) branched chain of glucose molecules linked by α-1, 6 glycosidic bond at the site of branching (d) unbranched chain of glucose molecules linked by α-1, 4 glycosidic bond.

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Last Answer : (b) unbranched chain of glucose molecules linked by β-1, 4 glycosidic bond

With hydrocarbons, is chlorine the ONLY atom powerful enough to remove a hydrogen atom from an alkane?

Description : With hydrocarbons, is chlorine the ONLY atom powerful enough to remove a hydrogen atom from an alkane?

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What is the name of the simplest alkane ?

Description : What is the name of the simplest alkane ?

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Which of the following produces highest amount of energy upon oxidation? (1) Protein (2) Fat (3) Glucose (4) An alkane

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A compound of formula C6H12 does not react with concentrated sulfuric acid. The compound could be (a) Alkane (b) Cycloalkane (c) Alkene (d) Cycloalkene

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Which of the following is not a possible reaction of a carbocation? (a) addition of a nucleophile (b) rearrangement to a more stable carbocation (c) addition of a proton to form an alkane (d) loss of a β-hydrogen to form an alkene

Description : Which of the following is not a possible reaction of a carbocation? (a) addition of a nucleophile (b) rearrangement to a more stable carbocation (c) addition of a proton to form an alkane (d) loss of a β-hydrogen to form an alkene

Last Answer : addition of a proton to form an alkane

The higher reactivity of an alkene or alkyne, as compared to an alkane, is due to (a) sigma bonds (b) pi bonds (c) hydrogen bonds (d) None of these

Description : The higher reactivity of an alkene or alkyne, as compared to an alkane, is due to (a) sigma bonds (b) pi bonds (c) hydrogen bonds (d) None of these

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A compound reacts with steam in the presence of concentrated H2SO4 to give isopropyl alcohol. The compound could be (a) Alkane (b) Alkyne (c) Alkene (d) Allene

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Last Answer : Alkene

A compound of formula C3H8 does not react with bromine in CCl4 in the dark. The compound could be (a) Alkane (b) Cycloalkane (c) Alkene (d) Cycloalkene

Description : A compound of formula C3H8 does not react with bromine in CCl4 in the dark. The compound could be (a) Alkane (b) Cycloalkane (c) Alkene (d) Cycloalkene

Last Answer : Alkane

Chlorination of an alkane as compared to bromination proceeds (a) at a slower rate (b) at a faster rate (c) with equal rates (d) with equal or different rate depending upon the source of alkane

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Last Answer : at a faster rate

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Description : The six carbon cyclic alkane is called what?  

Last Answer : ANSWER: CYCLOHEXANE

What is the I-U-P-A-C (pron: eye-you pack) name for a cyclic alkane containing four carbons?

Description : What is the I-U-P-A-C (pron: eye-you pack) name for a cyclic alkane containing four carbons?

Last Answer : ANSWER: CYCLOBUTANE

Which of the following produces highest amount of energy upon oxidation? (1) Protein (2) Fat (3) Glucose (4) An alkane

Description : Which of the following produces highest amount of energy upon oxidation? (1) Protein (2) Fat (3) Glucose (4) An alkane

Last Answer : Fat

Which statements about alkenes and alkanes of corresponding chain lengths is true? (I) Alkenes have slightly lower melting points than alkanes (II) Alkenes have slightly higher melting points than alkanes (III) Alkenes have higher boiling points than alkanes (IV) Alkenes have lower boiling points than alkanes (a) I and III (b) II and IV (c) I and IV (d) II and III

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Last Answer : I and III

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Description : CONDENSED STRUCTURE OF THE FOLLOWING1. 5,5 – diethyl – 3,3 – dimethyl – 1 - octyne2. 2,4,4,6 – tetraethyl – 3,3 – nondiene3. 1,1,4,4 – tetramethylheptaneIDENTIFY IF ITS ALKANE ALKYNE ALKENE?

Last Answer : ℤ.

Which of the following alkane is synthesised from single alkyl halide by wurtz reaction:-

Description : Which of the following alkane is synthesised from single alkyl halide by wurtz reaction:-

Last Answer : Which of the following alkane is synthesised from single alkyl halide by wurtz reaction:- A. B. C. D.

How many carbon atoms are present in the alkane whose IUPAC name is 2,2,4-trimethylpentane?

Description : How many carbon atoms are present in the alkane whose IUPAC name is 2,2,4-trimethylpentane?

Last Answer : Five