Title HYDROCARBONS A-1.pdf ✅

CLASS : XIIth SUBJECT : CHEMISTRY DATE : DPP NO. :1 1 (d) Unsaturated molecules decolourise Baeyer’s reagent. 2 (c) An alkene on reductive ozonolysis gives 2-molecules of CH2(CHO)2. Hence, the alkene is 1, 4-cyclohexadiene. 3 (b) C2H5I + C3H7I + 2Na Ether C2H5C3H7;C4H10;C6H14 4 (d) Friedel-Craft’s acylation it involves the treatment of benzene with acetyl chloride or acetic anhydride in presence of anhydrous aluminium chloride. 5 (b) Oxidation of 1-butene first gives a mixture of propionic acid and formic acid. Formic acid, however, gets further oxidised to CO2 and H2O. Therefore, option (b) is correct. 7 (b) A compound is said to be aromatic if it meets of the following criteria. 1. The rings of the compound should be planer. 2. The cyclic system must contain (4π + 2)π-electrons. Only option (b) contains 6π-electron, so it is aromatic. 8 (b) CH3CH = CH2 B2H6 (CH3CH2CH2 )3B H2O2 CH3CH2CH2OH + H3BO3; (i) O3 (ii) H2O/Zn 2 OHC CHO CH2 + CH3 C Cl O AlCl3 COCH3+ HCl acetophenone Topic :-HYDROCARBONS SOLUTION S
The process is called hydroboration. 9 (b) (i)CH3 ―CH = CH ― CH3 O3 Zn H2O CH3CHO + CH3CHO + ZnO 2 molecules of ethanal (ii)C6H5CH = CH2 O3 Zn H2O C6H5CHO + HCHO + ZnO benzaldehyde methanol (iii)CH3CH = CH2 O3 Zn H2O CH3CHO + HCHO Ethanol methanol (iv)(CH3)2C = C(CH3 )2 O3 Zn H2O CH3COCH3 + CH3COCH3 + ZnO 2 molecules of acetone 11 (c) Alkynes are not found in free state due to their high reactivity. 12 (a) Least hindered rotation means free rotation, i.e., round a single bond. 13 (c) H2C = CH2 HBr CH3 ―CH2Br (X) Aq.KOH CH3 ―CH2OH Na2CO3 I2excess CHI3 (Y) (Z) iodoform 15 (b) In Wurtz reaction, an ether solution of an alkyl halide is treated with sodium which removes the halogen of alkyl halide and the two alkyl radicals join together to form an alkane 17 (d) An immiscible and lighter substance with water will float over it. 18 (d) These all are obtained from coal-tar. 19 (b)
For transproduct we take Na/liquid NH3 or Li ― NH3/C2H5OH or LiAlH4 as a reducing agnet (anti- addition) 20 (a) CH3CH = CH2 +HOCl +→CH3 ―CH ― CH2 Propyene hypochlorous | | acid OH Cl propene chlorohydrin R C C R + H2 Na/liq. NH3 or LiAlH4 C C H R R H trans-alkene
ANSWER-KEY Q. 1 2 3 4 5 6 7 8 9 10 A. D C B D B A B B B C Q. 11 12 13 14 15 16 17 18 19 20 A. C A C D B B D D B A