Description : What kind of combustion is observed in alkanes? Why do air holes of a gas burner have to be adjusted when vessel being heated gets blackened by the flame? -Science
Last Answer : Alkanes are saturated hydrocarbons and generally burn in air with a blue, non-sooty flame. If the bottoms of the cooking vessels in our homes are getting blackened, it shows that the air holes of the gas stove are getting blocked and the fuel is not burning completely.
Description : What is another name of alkanes?
Last Answer : Paraffins
Description : Long chain alkanes or alkenes containing terminal carboxylic acid ( – COOH) are called
Last Answer : fatty acid.
Description : The first member of the alkanes or saturated hydrocarbon is
Last Answer : methane.
Description : The general formula of alkanes is
Last Answer : C n H 2n+2
Description : Give reason: Alkanes undergo only substitution reactions but alkenes and alkynes undergo both substitution and addition reactions.
Last Answer : Alkenes and alkynes have double and triple bonds, which on breaking can add hydrogen atoms to satisfy the valency.
Description : Compare the characteristics of alkanes, alkenes and alkynes.
Last Answer : Alkanes Alkynes They are saturated They are unsaturated They are unsaturated Their general formula is C n H 2n+2 Their general formula is C n H 2n Their general formula is C n H 2n-2 They have ... ene' They have triple bond between one of the carbon atoms. Their names end with yne'
Description : Give reason: Alkanes are chemically stable.
Last Answer : In alkanes all carbon atoms are bonded to the maximum number of hydrogen atoms. They are made up single bond between carbon atoms and are saturated with hydrogen in every bond is used. Hence they are chemically stable.
Description : Why are alkanes referred to as paraffins?
Last Answer : Paraffin is derived from the Latin word meaning ‘less activity’. Alkanes are compounds which undergo few reactions. Hence they are referred to as paraffins.
Description : Mention the characteristics of alkanes.
Last Answer : a) In alkanes the carbon atoms are bonded with maximum number of hydrogen atoms. b) They have single bond between carbon atoms. c) Their general formula is C n H 2n+2
Description : Why do first three alkanes methane, ethane and propane have no isomers?
Last Answer : Methane (CH 4 ), ethane (C 2 H 6 ) and propane (C 3 H 8 ) have no scope for branching of C – C chain hence they do not exhibit isomerism.
Description : Thermal decomposition of alkanes is known as which name? -General Knowledge
Last Answer : The answer is 'Cracking'
Last Answer : answer:
Description : How many alkanes (only structural isomers) are possible with the molecular formula `C_(4)H_(8)`
Last Answer : How many alkanes (only structural isomers) are possible with the molecular formula `C_(4)H_(8)` A. 4 B. 3 C. 5 D. 6
Description : How can we separate Alkanes?
Last Answer : Need answer
Description : Saturated hydrocarbons are called - (1) Alkynes (2) Alkenes (3) Alkanes (4) All of the above
Last Answer : (3) Alkanes Explanation: Carbon compounds which contain just carbon and hydrogen are called hydrocarbons. Among these, the saturated hydrocarbons are called alkanes. The unsaturated hydrocarbons which contain one or more double bonds are called alkenes.
Description : Thermal decomposition of alkanes is known as which name?
Last Answer : Cracking
Description : What are alkanes? Why are they called paraffins?
Last Answer : Ans. Those hydrocarbons which contain single bond between carbon- carbon are called alkanes. They are called paraffins because they are very less reactive (Latin- Parum= little, affins = affinity)
Description : Arrange the following in order of decreasing reactivity towards alkanes. HCl, HBr, HI, HF
Last Answer : Ans. HI> HBr> HCl >HF
Description : Explain why Grignard reagents do not reacts with alkanes.
Last Answer : Ans. In alkanes , the C – H bond has very little polarity . The hydrogen cannot be abstracted by the Grignard reagent.
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.
Description : Why are alkanes called paraffins?
Last Answer : Paraffin’s means little affinity; alkanes due to strong C-C and C-H bonds are relatively chemically inert.
Description : What is the hybridization of carbon atoms in alkanes ?
Last Answer : Ans. Sp3
Description : Cycloalkanes have the same molecular formula as : (a) Alkanes (b) Alkenes (c) Alkynes (d) Cycloalkenes
Last Answer : Alkenes
Description : Ninhydrin test is given by (a) Carbohydrates (b) Proteins (c) Alkanes (d) Alkenes
Last Answer : Proteins
Description : The high boiling points of alcohols, as compared to the corresponding alkanes, are due to (a) Hydrogen bonding (b) Heavy oxygen atom (c) Water solubility (d) None of these
Last Answer : Hydrogen bonding
Description : 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 ... (a) I and III (b) II and IV (c) I and IV (d) II and III
Last Answer : I and III
Description : Which of the following methods can be used to increase the octane rating of gasoline? (a) Adding branched-chain alkanes (b) Adding tetraethyllead (c) Adding aromatic hydrocarbons (d) All of these
Last Answer : All of these
Description : Consider the three isomeric alkanes n-hexane, 2,3-dimethylbutane, and 2- methylpentane. Which of the following correctly lists these compounds in order of increasing boiling point? (a) 2,3-dimethylbutane < 2- ... < 2, 3-dimethylbutane < n-hexane (d) n-hexane < 2-methylpentane < 2,3-dimethylbutane
Last Answer : 2,3-dimethylbutane < 2-methylpentane < n-hexane
Description : The thermal decomposition of alkanes in the absence of air is called : (a) Combustion (b) Oxidation (c) Cracking (d) Hydrogenation
Description : In the chlorination of alkanes, the first step in which chlorine free radicals are produced is called : (a) initiation (b) activation (c) propagation (d) deactivation
Last Answer : initiation
Description : Why is the halogenation of alkanes considered a chain reaction? (a) it occurs quickly. (b) it occurs without the generation of intermediates. (c) each step generates the reactive intermediate that causes the next step to occur. (d) the reaction allows long chains of halogenated alkanes to be formed
Last Answer : each step generates the reactive intermediate that causes the next step to occur
Description : Which of the following classes of compounds is unreactive toward sulfuric acid? (a) Alkanes (b) Alcohols (c) Alkenes (d) Alkynes
Last Answer : Alkanes
Description : Which of the following reactions can be used to prepare alkanes? (a) Wurtz reaction (b) Wolf-kishner reduction (c) Kolbe's electrolysis (d) All of these
Description : Which of the following reactions can be used to prepare alkanes? (a) Corey-House synthesis (b) Williamson synthesis (c) Friedel-Crafts reactions (d) None of these
Last Answer : Corey-House synthesis
Description : Which of the following alkanes will have the lowest boiling point? (a) n-Heptane (b) Isopentane (c) n-Hexane (d) Neopentane
Last Answer : Neopentane
Description : Which of the following alkanes will have the highest boiling point? (a) n-Octane (b) Isopentane (c) n-Butane (d) Neopentane
Last Answer : n-Octane
Description : How do the boiling points of butane, propane, and ethane compare? (a) the boiling point of ethane is greatest. b) the boiling point of butane is greatest. (c) the boiling point of propane is greatest. (d) there is no relationship among these three alkanes and their boiling points
Last Answer : the boiling point of butane is greatest.
Description : How does the melting point of propane and ethane compare? (a) the melting point of propane is greater. (b) the melting point of ethane is greater. (c) the melting points are within 5°C of one another. (d) no relationship exists among these alkanes and their melting point
Last Answer : the melting point of ethane is greater.
Description : The branching of alkanes that produces symmetrical structures : (a) raises the boiling point ; raises the melting point (b) raises the boiling point ; lowers the melting point (c) lowers the boiling point ; lowers the melting point (d) lowers the boiling point ; raises the melting point
Last Answer : raises the boiling point ; raises the melting point
Description : As the molecular weight of alkanes increases, how do the boiling point and melting point change? (a) boiling point increases ; melting point increases. (b) boiling point increases ; ... decreases (d) boiling point increases ; melting point increases sequentially for alkanes over four carbons.
Last Answer : boiling point increases ; melting point increases sequentially for alkanes over four carbons.
Description : Which statement is false? (a) Many alkanes are soluble in water. (b) All alkanes have a lower density than water. (c) At room temperature some alkanes are liquids, some solids, some gases. (d) All alkanes burn
Last Answer : Many alkanes are soluble in water
Description : Which of the following show n→ ℿ * electronic transitions? a. Alcohols b. Ethers c.Alkanes d. Aldehydes
Last Answer : d. Aldehydes
Description : A family of organic compounds containing only carb and hydrogen and having only single bonds are the: w) alkenes and alkanes x) alkanes and cycloalkanes y) alkynes (pron: AL-kines) and alkenes z) cycloalkanes and alkenes
Last Answer : ANSWER: B -- ALKANES AND CYCLOALKANES
Description : Which of the following group of compounds is most soluble in water? w) alkanes (pron: ak-KANES) x) alcohols y) aldehydes (pron: al-deh-HIDES) z) alkenes (pron: al-KEENS)
Last Answer : ANSWER: X -- ALCOHOLS
Description : A family of organic compounds whose molecules will add water under an acid catalysis and change into alcohols are the: w) alkenes x) alkanes y) aromatic hydrocarbons z) cycloalkanes
Last Answer : ANSWER: W -- ALKENES
Description : Hydrocarbons that contain a triple bond between carbon atoms are known as: w) alkenes x) alkanes y) alkynes z) polymers
Last Answer : ANSWER: Y -- ALKYNES
Description : Which of the following are saturated aliphatic hydrocarbons? w) alkanes x) alkenes y) alkynes z) nixanes
Last Answer : ANSWER: W -- ALKANES
Description : Which of the following contain sp2 hybridized carbon atoms? w) alkanes x) alkenes y) alkynes z) cycloalkanes
Last Answer : ANSWER: X -- ALKENES