Description : Which of the following statements correctly describes the general reactivity of alkynes? (a) An alkyne is an electron-rich molecule and therefore reacts as a nucleophile. (b) The σ bonds ... fail to undergo electrophilic addition reactions. (d) Alkynes are generally more reactive than alkenes.
Last Answer : Alkynes are generally more reactive than alkenes.
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 : 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 : 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 : Cycloalkanes have the same molecular formula as : (a) Alkanes (b) Alkenes (c) Alkynes (d) Cycloalkenes
Last Answer : Alkenes
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 : 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
Description : Why do aldehydes undergo nucleophilic addition reactions while esters undergo nucleophilic acyl substitution reactions? (a) The carbonyl carbon of an ester is more electrophilic than that of an aldehyde. (b) ... adds to an aldehyde, neither H− nor R− can be eliminated since they are strongly basic
Last Answer : Once the nucleophile adds to an aldehyde, neither H− nor R− can be eliminated since they are strongly basic
Description : Which statement about the carbonyl group of ketones and aldehydes is true? I. It can attract nucleophiles. II. It can attract electrophiles. III. It tends to undergo addition reactions. IV. It tends to undergo substitution reactions. (a) I and III (b) II and IV (c) I, II, and III (d) I, III, and IV
Last Answer : I, II, and III
Description : Alkyl halides undergo (a) Electrophilic substitution reactions (b) Electrophilic addition reactions (c) Nucleophilic substitution reactions (d) Nucleophilic addition reactions
Last Answer : Nucleophilic substitution reactions
Description : Which of the following statements about alkenes and alkynes is correct? (a) Alkynes are reduced more readily than alkenes. (b) Alkynes are reduced less readily than alkenes. (c) Alkynes and alkenes are reduced with equal speed. (d) Alkynes and alkenes can not be reduced.
Last Answer : Alkynes are reduced more readily than alkenes.
Description : Benzene cannot undergo – (1) Substitution (2) Addition (3) Elimination (4) Oxidation
Last Answer : (3) Elimination Explanation: Benzene can not undergo Elimination reaction.
Description : Benzene cannot undergo : (1) Substitution (2) Addition (3) Elimination (4) Oxidation
Last Answer : Elimination
Description : Why does benzene undergo electrophilic substitution reactions easily and nucleophilic substitutions with difficulty?
Last Answer : Ans. Due to the presence of an electron cloud containing 6 pi electrons above and below the plane of the ring, benzene is a source of electrons. Consequently, it attracts ... . As a result, benzene undergoes electrophilic substitution reactions easily and nucleophilic substitution with difficulty.
Description : Which of the following is not correct concerning substitution and elimination reactions of alkyl halides? (a) The electrophile replaces the leaving group. (b) Compounds containing electron-donating groups bonded to an ... replaced by another atom or group in substitution reactions. (d) (a) and (b)
Last Answer : (a) and (b)
Description : Long chain alkanes or alkenes containing terminal carboxylic acid ( – COOH) are called
Last Answer : fatty acid.
Description : Ninhydrin test is given by (a) Carbohydrates (b) Proteins (c) Alkanes (d) Alkenes
Last Answer : Proteins
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 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 : An organic compound (A) has a molecular weight 78 and an empirical formula CH. (A) is resistant to attack by oxidizing agents but undergoes substitution and addition reactions. X-ray analysis shows that the ... suggests that compound (A) is (a) Benzene (b) Cyclohexane (c) Toluene (d) n-Hexane
Last Answer : Benzene
Description : Which of the following characterizes the reactions of aldehydes and ketones? (a) electrophilic addition (b) electrophilic substitution (c) nucleophilic acyl substitution (d) nucleophilic addition; free radical addition
Last Answer : nucleophilic addition; free radical addition
Description : Although benzene is highly unsaturated, it does not undergo addition reactions, why?
Last Answer : Ans. Because of extra stability, due to delocalization of π-electrons.
Description : In the addition of hydrogen bromide to alkynes, which of the following species is believed to be an intermediate? (a) vinyl anion (b) vinyl cation (c) vinyl radical (d) carbene
Last Answer : vinyl cation
Description : Which of the following can undergo nucleophilic substitution under ordinary conditions? I Allyl chloride II Benzyl chloride III n-Propyl chloride IV V
Last Answer : Which of the following can undergo nucleophilic substitution under ordinary conditions? I Allyl chloride II ... are correct D. I and III are correct
Description : Phenols do not undergo substitution of the — OH group like alcohols. Explain.
Last Answer : The C — O bond in phenols has some double bond character due to resonance and hence cannot be easily cleaved by a nucleophile. In contrast, the C — O bond in alcohols is a pure single bond and hence can be easily cleaved by a nucleo phile.
Description : Which of the following will undergo substitution in the ortho and para positions rather than in the meta position? (a) Nitrobenzene (b) Benzoic acid (c) Acetanilide (d) Benzaldehyde
Last Answer : Acetanilide
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
Last Answer : 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 : Benzene reacts with concentrated HNO3 in the presence of concentrated H2SO4 to give nitrobenzene. This reaction is an example of (a) Electrophilic addition (b) Nucleophilic addition (c) Electrophilic substitution (d) Nucleophilic substitution
Last Answer : Electrophilic substitution
Description : The chlorination of methane to give CCl4 is an example of (a) an electrophilic addition (b) a free-radical substitution (c) a nucleophilic addition (d) an electrophilic substitution
Last Answer : a free-radical substitution
Description : Give reason: Alkenes and Cycloalkanes have same general formula.
Last Answer : Alkenes and Cycloalkanes have same general formula because they have double bond between carbon atoms.
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 : Esters can be formed by nucleophilic substitution reactions of : (a) carboxylic acids and alcohols ; acid-catalyzed (b) acid chlorides and alcohols (c) both of the above (d) neither of the above
Last Answer : both of the above
Description : Adding Cl2 to benzene in the presence of AlCl3 is an example of – (1) Elimination reaction (2) Substitution reaction (3) None of the options (4) Addition reaction
Last Answer : (2) Substitution reaction Explanation: The reaction between benzene and chlorine in the presence of a catalyst such as aluminium chloride gives Chlorobenzene. This reaction is an example of electrophilic substitution ... since one of the hydrogen atoms on the ring is replaced by a chlorine atom.
Description : Benzene undergoes substitution reaction more easily than addition reaction because (a) it has a cyclic structure (b) it has three double bonds (c) it has six hydrogen atoms (d) there is delocalization of electrons
Last Answer : there is delocalization of electrons
Description : Which of the following is not a correct statement about the electrophilic substitution mechanism of benzene? (a) Benzene functions as a nucleophile. (b) Formation of a carbocation intermediate is the ... hybridized carbon in the ring. (d) The addition product is a frequently observed minor product.
Last Answer : The addition product is a frequently observed minor product.
Description : The characteristic reaction of carboxylic acids is : (a) electrophilic addition (b) electrophilic substitution (c) nucleophilic addition (d) nucleophilic substitution
Last Answer : nucleophilic substitution
Description : Acetone reacts with HCN to form a cyanohydrin. It is an example of (a) Electrophilic addition (b) Electrophilic substitution (c) Nucleophilic addition (d) Nucleophilic substitution
Last Answer : Nucleophilic addition
Description : Propene reacts with bromine to form 1,2-dibromopropane. This is an example of (a) Nucleophilic addition (b) Electrophilic addition (c) Nucleophilic substitution (d) Electrophilic substitution
Last Answer : Electrophilic addition
Description : Which one of the following could NOT cause a change in the mRNA ―reading frame‖? a. Insertion Sequence b. Base-Pair Substitution c. Base Addition d. Base Deletion
Last Answer : b. Base-Pair Substitution
Description : BHC (Benzene hexachloride) is made by the chlorination of benzene (A) Which is an addition reaction (B) Which is a substitution reaction (C) In absolute dark (D) In presence of sunlight
Last Answer : (A) Which is an addition reaction
Description : Adding Cl2 to benzene in the presence of AlCl3 is an example of : (1) Elimination reaction (2) Substitution reaction (3) None of the options (4) Addition reaction
Last Answer : Substitution reaction
Description : What addition reaction will hydrocarbon undergo?
Last Answer : What is the answer ?
Description : Explain why nucleophilic substitution reactions are not very common in phenols.
Last Answer : Explain why nucleophilic substitution reactions are not very common in phenols.