Title HYDROCARBONS A-2.pdf ✅

CLASS : XIIth SUBJECT : CHEMISTRY DATE : DPP NO. : 2 1 (b) CH ≡ CH + N2→2HCN 2 (a) The reaction is as follows 3 (b) The structure of benzene is Bond order = number of bonds number of resonating structures = 4 3 = 1.33 Since, the bond order is in between single and double bond, thus, it contains delocalised π- bonds. Hence, it is not possible to obtain number of single and double bonds in benzene. 4 (d) ― NO2 group withdraw electron from the ring shows ―M effect makes ring electron deficient, thus deactivates ring for electrophilic substitution. 5 (b) Reaction of a non-terminal alkyne with a solution of an alkali metal (usually Na or Li or K) in liquid ammonia give a transalkene. CH2 CH2 HBr CH3 CH2Br AgCN CH3CH2NHCH3 H2 /Ni reduction CH3CH2NC (Z) (X) N-methyl ethanamine (Y) 120 oC + X2 X (mono substituted product) Topic :-HYDROCARBONS SOLUTION S
CH3 ―C ≡ C ― CH3 +2[H] Li liq.NH3 6 (d) B.p. increases with increase in mol. Wt. 7 (b) 1. Benzene undergoes electrophilic substitution in presence of AlCl3 or FeCl3 or ZnCl2. 2. Benzene does not undergo addition reactions like alkene. ∴ C6H6 +HOCl H+ no product and (b) is correct answer. 8 (d) C ― H bond energy is greatest in ethyne due to the presence of triple bond. 9 (b) CH3—CH = CH—CH3 is planer molecule due to sp 2 ―sp 2 -hybridised carbon atoms. 10 (a) TEL increases the octane no. of gasoline. 11 (d) The refining of petroleum is distillation process. 12 (b) It is how Zn-Cu couple is used. 13 (b) CH3—C ≡ C—CH3 is linear and symmetrical and thus, dipole moment is zero. 15 (a) RCOONa⟶R—R + 2CO2 + 2NaOH + H2 17 (b) Only terminal alkynes give precipitate with ammoniacal silver nitrate solution. Among the given, CH3 ―C ≡ CH ― CH3 is not a terminal alkyne. Thus, it does not give precipitate with ammoniacal AgNO3. 19 (c) Benzene vapours mixed with air when passed over V2O5 catalyst at 775 K gives maleic anhydride 20 (a) 2CH3CH2CH2COONa→ Anode CH3CH2CH2CH2CH2CH3 + 2CO2 Cathode + 2NaOH + H2 H3C H C C CH3 H benzene+ 9 2 O2 V2O5 773 K CH CH COOH COOH maleic acid -H2O CH CH C C O O O maleic anhydride
ANSWER-KEY Q. 1 2 3 4 5 6 7 8 9 10 A. B A B D B D B D B A Q. 11 12 13 14 15 16 17 18 19 20 A. D B B A A B B C C A