(c) Cis and trans isomers have the same molecular formula, the same … Anonymous. Favorite Answer. Consequently, the boiling points of the branched chain alkanes are less than the straight chain isomers. What has the highest boiling point out of natural gases-lubricating oil-gasoline-kerosene-fuel oil. ; Ethanoic acid (CH 3 COOH): 118.1 0 C . (b) Alkanes that are liquid at room temperature are more dense than water. Thus, if two alkanes have the same molecular weight, the more highly branched alkane will have a lower boiling point." Methane (CH 4): -161.5 0 C - You see, methane (simplest alkane) has a very low boiling point. The lightest one: methane. Alkanes generally have low boiling points. Methane and ethanoic acid are belongs to two types of organic compounds and according to the type of type, there is a considerable boiling point … 4 Answers. Roger the Mole. With the increase in the number of carbon atoms, the molecular mass and also the molecular size increases. What Is the IUPAC nane of this compound? Therefore, the intermolecular attractive forces which depend upon the surface area, also become small in magnitude on account of branching. N Ethane B) Butane C) Octane D) Hexane E) Propane 12. lubricating oil. Larger molecules have greater surface areas and consequently interact more strongly; more energy is therefore required to separate them. BOILING POINTS. But cycloalkanes have less possible conformations and so stack better this lets them get closer to each other and hence have stronger interactions and a higher boiling point because of that. Therefore, it seems as though the answer for the question about comparing the boiling point of 2-Methylpentane and 3-Methylpentane lies in the reason for why an "iso-" alkane has the lowest boiling point for an n-carbon alkane. Which alkane has the lowest boiling point? Answer Save. How many secondary carbons are in the molecule (CH3)2CH(CH2)2CH3? ethane. of all organic compounds _____ have the lowest melting and boiling points. In all these cases, it seems as though the 2-methyl isomer (the "iso-" isomer) has the lowest boiling point. 2. Boiling point of methane and ethanoic acid. Which alkane has the lowest boiling point? 5 years ago. Lv 7. Ethanoic acid has a higher boiling point than water. (a) Boiling points among alkanes with unbranched chains increase as the number of carbons in the chain increases. This can be explained on the basis of interparticle forces. Alkanes The boiling points of *branched* alkanes are generally lower or higher than straight-chain isomers. Relevance. Where you have isomers, the more branched the chain, the lower the boiling point tends to be. Even for isomeric alkyl halides, the boiling points … A) Ethyl methy1 eyclopropane 8) Ethy1-2-nethyleyclobutane C 1-ethyl-2 methylcyclobutane b) 1-uthyl-2-methylcyclotriane ? 1 decade ago. Consequently, the boiling points of the branched chain alkanes are less than the straight chain isomers. i-ethyl-hethylcyclapropan" 2. For a given molar mass, the boiling points of alkanes are relatively low because these nonpolar molecules have only weak dispersion forces to … The boiling points of n-alkanes increase regularly with the increase in the number of carbon atoms. 11. Which alkane has the lowest boiling point out of octane-butane-ethane-hexane-propane. 0 0. The above extract from my book, mentions clearly that branching makes the molecule more compact and thereby decreases the surface area. In magnitude on account of branching in magnitude on account of branching the same molecular weight, the attractive! 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