Tiêu đề ORGANIC CHEMISTRY - SOME BASIC PRINCIPLES AND TECHNIQUES A-5.pdf ✅

CLASS : XIIth SUBJECT : CHEMISTRY DATE : DPP NO. : 5 1 (b) Formic acid was obtained from ant (fromica in greek). This is trivial name for HCOOH. 2 (a) The structure of 2, 3-dimethyl hexane is So, the number of tertiary carbon atoms=2 The number of secondary carbon atoms=2 The number of primary carbon atoms=4 3 (a) Follow IUPAC rules. 6 (c) CH+ 3 has planar structure. 7 (d) These are characteristics of carbanion. 8 (a) Follow Saytzeff rule for elimination. 3-halopentane will give only pentene-2. 9 (b) Atom Atomic Percentage b a = x Ratio Mass (a) (b) C 12 10.06 10.06 12 1 H 1 0.84 0.84 1 1 Cl 35.5 89.10 89.10 35.5 3 Empirical formula = CHCl3 Empirical formula mass = 12 + 1 + 106.5 = 119.5 ≈ 120 Molecular mass = 2 × V.D = 2 × 60 = 120 H3C CH CH CH3 CH3 CH2 CH2 CH3 1 o 3 o 3 o 1 o 1 o 2 o 2 o 1 o Topic :-ORGANIC CHEMISTRY - SOME BASIC PRINCIPLES AND TECHNIQUES SOLUTION S
n = molar mass empirical formula mass = 120 120 = 1 Molecular formula = (CHCl3 )1 = CHCl3 10 (d) During nucleophilic substitution weaker nucleophile is replaced by stronger nucleophile. The compound having C-Cl bond which can be most easily broken will be most reactive towards nuclophilic substitution reaction. In vinyl chloride CH2 = CH ― Cl and chlorobenzene C6H5Cl the C ― Cl bond has partial double bond character due to resonance. ∴ They do not give nucleophilic substitution reaction easily Benzyl chloride, give nucleophilic substitution easily because they carbocation formed is stabilised due to resonance. 11 (a) Enantiomers are non-superimposable mirror images, e.g, lactic acid Diastereomers are non-superimposable and are not the mirror images of each other. Moreover, meso form has plane of symmetry. 12 (b) Nucleophilic strength increases down a column of the Periodic Table (in solvents that can have hydrogen bonds, such as water, alcohols, thio alcohols). Nucleophilic strength RO ― < RS ― Base strength RO⊝ > RS ― Thus, RO⊝ is more nucleophilic but less basic than RO ― CH2 CH Cl CH2 - CH Cl CH2Cl CH2 CH CH2Cl -Cl - CH2 CH CH2 allyl chloride allyl CH2 CH CH2 carbocation OH - HOCH2 CH CH2 allyl alcohol C CH3 H COOH OH C CH3 OH COOH H
15 (a) We know that there are seven isomers in C4H10O. Out of these seven isomers, four are of alcohol and three are of ether. 16 (a) Tertiary halide always favours SN1 mechanism (as they give comparatively stabler carbocation) white primary halide favours SN2 mechanism. 17 (d) Electron donors are bases. Since, electron density is highest at (Piperidine), hence, it is most basic. 18 (d) Follow IUPAC rules. 20 (c) To be optically active, compound or structure should posses a chiral or asymmetric carbon atom. 1- chloropentane is not chiral. N H
ANSWER-KEY Q. 1 2 3 4 5 6 7 8 9 10 A. B A A C C C D A B D Q. 11 12 13 14 15 16 17 18 19 20 A. A B C A A A D D A C