Tiêu đề ORGANIC CHEMISTRY - SOME BASIC PRINCIPLES AND TECHNIQUES A-4.pdf ✅

CLASS : XIIth SUBJECT : CHEMISTRY DATE : DPP NO. : 4 1 (a) Racemisation involves change in entropy, i.e., change in arrangement of groups position leading to a change in entropy of disorderness. 2 (a) The acyclic stereoisomers of C4H7Cl are Number of optical isomers =2 n = 2 1 = 2 (i) C C H2CH3C H H Cl cis form (ii) C C H2CH3C H Cl H trans form (i) C C H CH2Cl CH3 H cis form (ii) C C H CH2Cl H CH3 trans form (i) C C H3C Cl CH3 H cis form (ii) C C Cl H3C CH3 H trans form H2C CH C H CH3 Cl * 2 optical isomers 2 geometrical isomers 2 geometrical isomers 2 geometrical isomers Topic :-ORGANIC CHEMISTRY - SOME BASIC PRINCIPLES AND TECHNIQUES SOLUTION S
Hence, total number of geometrical isomers=6 Total number of optical isomers =2. 3 (c) This compound contains 7 carbon atoms, so the corresponding alkane is heptane. Two bridges contain 4 and 1 carbon atom respectively and one bridge does not contain any carbon atom. So the name of the compound is bicyclo (4,1,0) heptane. 4 (d) Stability of alkyl free radicals can be explained by hyperconjugation and number of resonating structure due to the hyperconjugation. The decreasing order of stability of alkyl free radical is as follows 6 (b) Inductive effect involves only displacement (and not delocalisation) of σ ― electrons. 7 (c) Meso forms are optically inactive as they are superimposable to their mirror images. 8 (b) CH4 has highest ratio of H to C 9 (b) When methylene group ( ― CH2) is attached with two electron withdrawing groups (like, ― CHO, > C = O, ― COOH, ― CN, ― X, etc), its acidity will increase due to –I effect of the electron withdrawing groups. 10 (a) Follow IUPAC rules. 11 (c) The reactivity order for H atom is 3° > 2° > 1°; Neocarbon does not have H atom. 13 (b) —do— 14 (a) Organic compound which are volatile in steam can be purified by steam distillation. It is based on the fact that vaporisation of organic liquid takes place at lower temperature than its boiling point 15 (b) Follow IUPAC rules. bicyclo (4, 1, 0) heptane 3 o free radical > 2 o free radical > 1 o free radical > CH3 H3C CH2 C CH2 O C CH3 O 2, 4-hexanedione active methylene group
17 (d) CH3Ō is nucleophile; 18 (a) Inductive effect is the permanent effect on σ ― electrons. It involve the electron displacement along the chain of saturated carbon atoms due to the presence of a polar covalent bond at one end of the chain. 19 (c) Homologous differ by a group —CH2and cannot be isomer. 20 (c) The reagent selected should be such that only one of components to be separated, reacts with it. Aniline+aq. HCl→salt, which is water soluble Nitrobenzene +aq. HCl→no reaction ∴ aq. HCl is used to separate aniline and nitrobenzene. CH3OH+ Na CH3O Na + +(1/2)H2.
ANSWER-KEY Q. 1 2 3 4 5 6 7 8 9 10 A. A A C D B B C B B A Q. 11 12 13 14 15 16 17 18 19 20 A. C C B A B C D A C C