Tiêu đề HYDROCARBONS A-3.pdf ✅

CLASS : XIIth SUBJECT : CHEMISTRY DATE : DPP NO. : 3 1 (d) Compound has 8 + 2 = 10π electrons hence is aromatic. has 4πe ― , has 8πe ― , while has 8 + 1 = 9πe ― , hence all these species are not aromatic 2 (b) It is a mixture of solid hydrocarbons. 3 (c) This reaction is an example of Diel’s Alder reaction 4 (d) All of these can be used in cracking. 5 (b) General formula of a cycloalkane is CnH2n. 6 (b) Toluene reacts with excess of Cl2 in presence of sunlight, the last product of this reaction is benzotrichloride which on hydrolysis gives benzoic acid, and it gives sodium benzoate on reaction with NaOH. 2- - C6H5 C6H5 + C C CN CN 2,3-diphenyl- 1,3-butadiene dicyanoethyne C6H5 C6H5 CN CN Topic :-HYDROCARBONS SOLUTION S
8 (d) CH3CH2COOH + NaHCO3⟶CH3CH2COONa + H2O + CO2 9 (a) C2H2 + 5 2 O2⟶2CO2 + H2O; 1 mole or 1 vol. of C2H2 requires 2.5 mole or 2.5 vol. of O2. 10 (a) Conjugate dienesare mores stable than the other dienes. 11 (c) Branched chain alkanes give rise to increase on octane no. 12 (d) Follow Markownikoff’s rule. 13 (b) HOCl has Cl + and OH ― ions 14 (b) Zn ― H2O is the reagent for reductive work up of ozonide. H2O2 ―CH3COOH would give HOOC ― (CH2 )4 ―COOH. 15 (d) The π-bond is unshared in electromeric effect to give +ve and –ve centres on molecule. CH3 toluene + Cl2 Sunlight CH2Cl Cl2 -HCl CHCl2 benzal chloride Cl2 -HCl CCl3 benzo trichloride OH - HOH COOH benzoic acid NaOH COONa sod. benzoate CH3CH CH2 + Cl+ Electrophilic addition CH3 CH CH2 Cl + OH - CH3 CH CH2 OH Cl CHO CHO (i) O3 (ii) Zn - H2O CH2 CH2 A.R. CH4 + CH4
16 (d) Tropylium cation is planar and have 6π-electron according to Huckel rule, hence it is aromatic. Cyclopentadienyl anion is planar and have 6π-electron, hence it is also aromatic compound. 17 (a) Follow peroxide effect. 18 (a) In the laboratory, nitrobenzene is prepared by nitration of benzene with the mixture of nitric acid and sulphuric acid at temperature below60°C. In which HNO3 acts as a base 19 (d) The reaction is ozonolysis. During the reaction C = C breaks to give carbonyl compounds. CH3CH = CH2 O3 H2O2 CH3CHO + HCHO Acetaldehyde formaldehyde 20 (a) Petrol or gasoline contains mainly C6 to C11atoms liquid alkanes. + -
ANSWER-KEY Q. 1 2 3 4 5 6 7 8 9 10 A. D B C D B B D D A A Q. 11 12 13 14 15 16 17 18 19 20 A. C D B B D D A A D A