Hydrocarbons PYQs Set 1 (PDF)

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Mere Teacher · Previous Year Questions NEET Chemistry · Hydrocarbons · Set 1 (Q1-30)
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1. $According to Bayer's strain theory which is highly stable?$ (1) $Cyclobutane$ (2) $Cyclopentane$ (3) $Cycloheptane$ (4) $Cyclohexane$ 2. $Which of these will produce the highest yield in Friedel Craft reaction?$ (1) (2) (3) (4) 3. $Which one of the following methods is suitable to generate aromatic compound(s) from linear aliphatic saturated hydrocarbons with at least six carbon atoms?$ (1) $Heating at 773 K$ (2) $Mo_{2} O_{3}, 773 K, 10 - 20 atm$ (3) $Anhyd. AlCl_{3}, conc. HCl, Δ$ (4) $Cu, 523 K, 100 atm$ 4. $Which of the following statements is correct in the Kolbe's electrolysis?$ (1) $Hydrocarbons containing even number of carbon atoms produced at anode$ (2) $Hydrocarbons containing odd number of carbon atoms produced at anode$ (3) $Hydrocarbons containing even number of carbon atoms produced at cathode$ (4) $Hydrocarbons containing odd number of carbon atoms produced at cathode$ 5. $Which of the following reagents will be ableto distinguish between 1‐butyne and 2‐butyne?$ (1) $N a N H_{2}$ (2) $HC1$ (3) $O_{2}$ (4) $B r_{2}$ 6. $In the chemical reaction, CH_{3} CH_{2} NH_{2} + CHCl_{3} + 3KOH \to (a) + (b) + 3H2O, the compounds (a) and (b) are respectively,$ (1) $C_{2} H_{5} NC and K_{2} C O_{3}$ (2) $C_{2} H_{5} NC and 3KCl$ (3) $C_{2} H_{5} CN and 3KCl$ (4) $C H_{3} C H_{2} C O N H_{2} and 3KCl$ 7. $The trans-alkenes are formed by the reduction of alkynes with :$ (1) $Na/liq. N H_{3}$ (2) $Sn - HCl$ (3) $H_{2} -Pd/C, B a S O_{4}$ (4) $N a B H_{4}$ 8. $Consider the nitration of benzene using mixed conc. H2SO4 and HNO3 . If a larger amount of KHSO4 is added to the mixture the rate of nitration will be :$ (1) $doubled$ (2) $faster$ (3) $slower$ (4) $unchanged$ 9. $In the commercial gasolines, the type ofhydrocarbons which are more desirable is$ (1) $linear unsaturated hydrocarbon$ (2) $toluene$ (3) $branched hydrocarbon$ (4) $straight‐chain hydrocarbon.$ 10. $Which of the following organic compounds has same hybridization as its combustion product -(CO2) ?$ (1) $Ethane$ (2) $Ethyne$ (3) $Ethene$ (4) $Ethanol$ 11. $Which of the following compounds will not undergo Friedel‐Crafts reaction easily?$ (1) $Nitrobenzene$ (2) $Toluene$ (3) $Cumene$ (4) $Xylene$ 12. $Reactivity of hydrogen atoms attached to different carbon atoms in alkanes has the order$ (1) $tertiary > primary > secondary$ (2) $primary > secondary > tertiary$ (3) $both (a) and (b)$ (4) $tertiary > secondary > primary.$ 13. $In the following the most stable conformation of n ‐butane is$ (1) (2) (3) (4) 14. $Which of the following reaction is not feasible?$ (1) $CH_{3} - CH_{2} - OH \to 95 % H 2 SO 4443 K CH_{2} = CH_{2}$ (2) $H_{3} C - CH_{2} - CH_{2} - CH_{2} - OH \to 75 % H 2 SO 4300 K CH_{3} - CH_{2} - CH = CH_{2}$ (3) $H_{3} C - C H_{2} - C H (O H) - C H_{3} 85% H_{3} P O_{4} 440 K C H_{3} - C H = C H - C H_{3}$ (4) $C H_{3} - C (C H_{3}) (C H_{3}) - O H 20% H_{3} P O_{4} 358 K C H_{3} - C (C H_{3}) = C H_{2}$ 15. $The most suitable solvent for Wurtz reaction is$ (1) $Dry acetonitrile$ (2) $Dry dichloromethane$ (3) $Dry ethanol$ (4) $Dry ether$ 16. $Given below are two statements: Statement I: One mole of propyne reacts with excess of sodium to liberate half a mole of H_{2} gas Statement II: Four g of propyne reacts with NaNH_{2} to liberate NH_{3} gas which occupies 224 mL at STP. choose the most appropriate answer from the options given below:$ (1) $Statement I is incorrect but Statement II is correct$ (2) $Both Statement I and Statement II are correct$ (3) $Statement I is correct but Statement II is incorrect$ (4) $Both Statement I and Statement II are incorrect$ 17. $Which of the following sets of functional groups is meta-directing group?$ (1) $- NO_{2}, - NH_{2}, - COOH, - COOR$ (2) $- NO_{2}, - CHO, - SO_{3} H, - COR$ (3) $- CN, - CHO, - NHCOCH_{3}, - COOR$ (4) $- CN, - NH_{2}, - NHR, - OCH_{3}$ 18. $The correct order of acidic nature of the following alkynes is I. C_{2} H_{2} II. (CH_{3})_{2} C_{2} III. (CH_{3}) C_{2} H$ (1) $I < III < II$ (2) $II < III < I$ (3) $III < II < I$ (4) $II < I < III$ 19. $Given below are two statements: Statement (I) : The NH_{2} group in Aniline is ortho and para directing and a powerful activating group. Statement (II) : Aniline does not undergo Friedel Craft's reaction (alkylation and acylation). In the light of the above statements, choose the most appropriate answer from the options given below :$ (1) $Both Statement I and Statement II are correct$ (2) $Both Statement I and Statement II are incorrect$ (3) $Statement I is incorrect but Statement II is correct$ (4) $Statement I is correct but Statement II is incorrect$ 20. $Which one of the following functional groups is not meta directing?$ (1) $- COOH$ (2) $- NO_{2}$ (3) $- CHO$ (4) $- OCH_{3}$ 21. $Which one of the following has the most nucleophilic nitrogen?$ (1) (2) (3) (4) 22. $The carbon-carbon bond length in benzene is$ (1) $same as in C_{2} H_{4}$ (2) $in between C_{2} H_{6} and C_{2} H_{2}$ (3) $in between C_{2} H_{4} and C_{2} H_{2}$ (4) $in between C_{2} H_{6} and C_{2} H_{4} .$ 23. $The product Z of the following reaction is H_{3} CC \equiv CH \to 2 HBr Z$ (1) $H_{3} CCH_{2} CHBr_{2}$ (2) $H_{3} CCBr_{2} CH_{3}$ (3) $H_{3} CCHBrCH_{2} Br$ (4) $BrCH_{2} CH_{2} CH_{2} Br$ 24. $Alkyl halides react with dialkyl copper reagents to give$ (1) $alkenes$ (2) $alkyl copper halides$ (3) $alkanes$ (4) $alkenyl halides$ 25. $Identify the correct statements from the following (i) Petrol and CNG operated automobiles cause less pollution (ii) Alkanes having tertiary hydrogen can be oxidised to alcohols by KMnO_{4} (iii) Methane can be prepared by Kolbe's electrolytic method. (iv) Alkyl chloride on reduction with zinc and dilute hydrochloric acid gives alkane$ (1) $(i), (iii), (iv)$ (2) $(i), (ii)$ (3) $(i), (ii), (iv)$ (4) $(iii), (iv)$ 26. $The major product obtained when ethanol is heated with excess of conc. H_{2} SO_{4} at 443 K is$ (1) $ethane$ (2) $methane$ (3) $ethene$ (4) $ethyne.$ 27. $Identify ortho and para directing groups from the following : - CHO, - NHCOCH_{3}, - OCH_{3}, - SO_{3} H I II III IV$ (1) $III, IV$ (2) $II, III$ (3) $II, IV$ (4) $I, IV$ 28. $Which cycloalkane has the lowest heat of combustion per CH_{2} group?$ (1) $Cyclopropane$ (2) $Cyclobutane$ (3) $Cyclopentane$ (4) $Cyclohexane$ 29. $Which one of the following is an intermediate in the reaction of benzene with CH_{3} Cl in the presence of anhydrous AlCl_{3} ?$ (1) $Cl^{+}$ (2) $CH_{3}^{-}$ (3) $CH_{3}^{+}$ (4) 30. $What are X and Y in the following reaction? Pent - 2 - ene \to (i) O 3 Zn / H 2 O X + Y X Y$ (1) $CH_{3} CHO CH_{3} CH_{2} CHO$ (2) $CH_{3} CH_{2} CHO CH_{3} CH_{2} CHO$ (3) $CH_{3} CHO (CH_{3})_{2} CO$ (4) $CH_{3} CHO CH_{3} CHO$