Concept explainers
Interpretation:
The stability of propyne and allene on the basis of heat of hydrogenation is to be determined. The reason why isomerization of an allene with a strong base leads to the formation of propyne is to be explained.
Concept introduction:
舧 Electrophiles are electron-deficient, species, which has positive or partially positive charge. Lewis acids are electrophiles, which accept electron pair.
舧 Nucleophiles are electron-rich species, which has negative or partially negative charge. Lewis bases are nucleophiles, which donate electron pair.
舧 Free radical is an atom, molecule, or ion that has an unpaired electron, which makes it highly chemically reactive.
舧 Substitution reaction: A reaction in which one of the hydrogen atoms of a hydrocarbon or a functional group is substituted by any other functional group is called substitution reaction.
舧 Elimination reaction: A reaction in which two substituent groups are detached and a double bond is formed is called elimination reaction.
舧 Addition reaction: It is the reaction in which unsaturated bonds are converted to saturated molecules by the addition of molecules.
舧 The reaction in which the halide group and hydrogen group are removed to form alkene is called dehydrohalogenation.
舧 The reaction in which hydrogen is added to the compound in the presence of catalyst is known as hydrogenation.
舧 The number of moles of hydrogen absorbed will be equal to the number of double bonds.
舧 Heat of hydrogenation in unsaturated compounds, like
舧 The smaller the numerical value of heat of hydrogenation of an unsaturated bond, the more stable is the unsaturated bond.
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Chapter 13 Solutions
Organic Chemistry
- An optically active monoterpene (compound A) with molecular formula C10H18O undergoes catalytic hydrogenation to form an optically inactive compound with molecular formula C10H20O (compound B). When compound B is heated with acid, followed by reaction with O3 and then with dimethyl sulfide, one of the products obtained is 4-methylcyclohexanone. Give possible structures for compounds A and B.arrow_forwardCompound P (C2H4) which is an alkene undergoes reaction with HCl to produce compound Q (C2H5Cl). Reaction of compound Q with benzene in the presence of AlCl3 as catalyst produces compound R. Then, nitration of compound R in the presence ofnH2SO4 produces two compounds, S and T. But when compound R is reacted with a hot acidified solution of alkaline KMnO4 gives compound U. Deduce the structure of compounds P to U.arrow_forwardEstablish the reaction and propose a mechanism for the reaction of benzene with bromine catalyzed with ferric bromidearrow_forward
- Explain the Mechanism - Addition of Dichlorocarbene to an Alkene ?arrow_forwardIdentify the pericyclic reaction benzocyclobutane E undergoes on heating, give astructure for intermediate H, and provide a mechanism that accounts for itsformation.arrow_forwardCompound A(C10H12O)gives off oxygen on treatment with sodium metal and also decolorizes Br2 in CCl4 to give organic compound B. Compound A on treatment with I2 in NaOH gives iodoform and salt C which after acidification gives a white solid D(C7H6O2). Using knowledge of organic chemistry identify structures A,B,C and Darrow_forward
- One step in the synthesis of dodecahedrane involves reaction of the tetraene C with dimethylacetylene dicarboxylate (D) to afford two compounds having molecular formula C16H16O4. This reaction has been called a domino Diels–Alder reaction. Identify the two products formed.arrow_forwardOn being heated with a solution of sodium ethoxide in ethanol, compound A (C7H15Br) produced a mixture of two alkenes B and C, each of which had the molecular formula C7H14. Catalytic hydrogenation of major isomer B or minor isomer C gave only 3-ethylpentane. Suggest structures and mechanisms for compounds A, B, and C consistent with these observations.arrow_forwardDescribe the ozonolysis of alkenes one mole of a hydrocarbon(A) reacts with one mole of beomine giving a dibromo compound C5H10Br2.Substance A on treatment with cold dilute kMnO4 solution forms a compound C5C12O2(C5H12O2) on ozonolysis A,gives equimolar quantities of propanone and ethanol.Deduce the structure of substance A.arrow_forward
- Provide a mechanism for the following reaction and rationalise the reactivity in terms of the 3 dimensional structure of the starting material and a consideration of the appropriate orbital interactions.arrow_forwardThe endiandric acids comprise a group of unsaturated carboxylic acids isolated from a tree that grows in the rainforests of eastern Australia. The methyl esters of endiandric acids D and E have been prepared from polyene Y by a series of two successive electrocyclic reactions: thermal ring closure of the conjugated tetraene followed by ring closure of the resulting conjugated triene. (a) Draw the structures (including stereochemistry) of the methyl esters of endiandric acids D and E. (b) The methyl ester of endiandric acid E undergoes an intramolecular [4 + 2] cycloaddition to form the methyl ester of endiandric acid A. Propose a possible structure for endiandric acid A.arrow_forwardTwo isomers, A and B, of molecular formula C5H8 undergo catalytic hydrogenation with hydrogen gas and palladium on carbon to form the same C5H10 product. On ozonolysis followed by treatment with hydrogen peroxide (H2O2), isomer A gave a product of molecular formula C5H8O4 that has two carboxylic acid groups in it whereas isomer B gave a product of molecular formula C5H8O3 that contains a carboxylic acid group and a ketone group. Which of the following isomeric pairs best match this data?arrow_forward
