NCERT Class 11 Chemistry Chapter 13 Hydrocarbons Very Short Answer Questions

NCERT Solutions For Class 11 Chemistry Chapter 13 Hydrocarbons Very Short Questions And Answers

Question 1. Which hydrocarbon is obtained on hydrolysis of Al₄C₃?
Answer: CH₄

Question 2. Name an alkane that cannot be prepared by the Wurtzreaction.
Answer: CH₄

Question 3. Which alkane is expected to be formed when ethyl magnesium bromide is allowed to react with water?
Answer: Ethane

Question 4. How many acyclic isomers of C₅H₁₂ are possible?
Answer: Isomer

Question 5. What is the main constituent of CNG?
Answer: CH₄

Question 6. Which type of aliphatic hydrocarbon undergoes substitution reaction?
Answer: Saturated

Question 7. What is the name of the alkene obtained when an aqueous solution of potassium succinate is electrolyzed?
Answer: Ethylene

Question 8. CH₃CH=CH₂HCl/peroxlde?
Answer: CH₃CHClCH

Question 9. Which alkene on ozonolysis yields only acetaldehyde?
Answer:  2-butene

Question 10. What is Baeyer’s reagent? What is its use?
Answer:  Alkaline KMnO₄ ,it is used to identify C=C and C=C;

Question 11. What is Lindlar’s catalyst?
Answer: Pd-CaCO₃/ (CH₃COO)₂Pb

Question 12. What is Teflon?
Answer: Polytetrafluoroethylene

Question 13. 2-butanone and ethanal are obtained when an alkene containing five carbon atoms is subjected to ozonolysis. State the position of the double bond in the alkene.
Answer: Doublebondis at C-2 of the alkene containing five carbon atoms

Question 14. What is mustard gas?
Answer:  2,2′- dichloro-diethyl sulfide;

Question 15. Name a reagent which can be used to distinguish between 2-butyne and 1-butyne.
Answer: Ammoniacal Cu₂Cl₂

Question 16. Which alkyne is used in Hawker’s Lamp?
Answer: HC=CH

Question 17. Mention the name of the compound obtained when acetylene reacts with arsenic chloride.
Answer: Lewisite

Question 18. What is the chemical name of Westron?
Answer: 1, 1,2,2- tetrachloroethane

Question 19. Mention one use ofWestrosol.
Answer: As an organic solvent

Question 20. What is obtained when acetylene is passed through a hot iron tube?
Answer: C₆H₆

Question 21. Give an example of an anti-knock compound.
Answer: Tetraethyl lead

Question 22. Which of the following cannot produce white precipitate by the action of ammoniacal AgNO₃—Acetylene, dimethyl acetylene, methyl acetylene, ethyl acetylene. one acts as the base
Answer: Dimethyl acetylene

Question 23.  Name the reagent which is used to carry out dihydroxylation of a double bond.
Answer: OsO₄ followed by hydrolysis;

Question 24. Which polymer is used to make carry bags? Name its monomer.
Answer: 5. Polyethylene or Polythene, ethylene;

Question 25. Which compound is formed as the major product when propyne reacts with 20% H₂SO₄ in the presence of 1% HgSO₄ at 80°C?
Answer: . Acetone (CH₃COCH₃)

Question 26. What is the state of hybridization of each carbon atom in an aromatic ring?
Answer: sp²

Question 27. Name the compound obtained by ozonolysis of benzene.
Answer: Glyoxal

Question 28. Give an example of a group that increases the rate of aromatic electrophilic substitution reaction.
Answer: —NH₂

Question 29. Give an example of a group that decreases the rate of aromatic electrophilic substitution reaction.
Answer: —NO₂

Question 30. Name an ortho-/para-orienting group.
Answer: Methyl (-CH₃)

Question 31. Name a meta-orienting group.
Answer: Nitro ( —NO₂)

Question 32. Give an example of a reversible electrophilic substitution reaction.
Answer: Sulphonationreaction

Question 33. Which is the smallest aromatic molecule/ion?
Answer: cyclopropenyl cation

Question 34. What is the orientation of the deactivating halogen atoms?
Answer: Ortho-/para

Question 35. Which heterocyclic compound remains as an impurity in benzene obtained from fractional distillation of coal tar?
Answer: Thiophene

Question 36. Which reagent is used in Birch reduction?
Answer: Na / liquid NH₃, ethanol

Question 37. Which type of flame is observed during the combustion of benzene?
Answer: Sooty flame

Question 38. Nitration occurs at which position of the compound
Answer: Predominantly para position

Question 39. Which electrophile is involved in the desulphonation reaction
Answer:  Proton (H⁺);

Question 40. Give an example of a carcinogen
Answer: 1, 2-benzpyrene

Question 41. Between HNO₃ and H₂SO₄ which one acts as the base during the formation of N02 ion?
Answer: HNO₃

Question 42. Which is the rate-determining step in an aromatic electrophilic substitution reaction?
Answer: First step, i.e., formation of σ -complex;

Question 43. Which step in aromatic electrophilic substitution reaction is exothermic?
Answer: Second step i.e., formation of substituted compound;

Question 44. Give an example of a neutral electrophile that participates in an electrophilic substitution reaction.
Answer: Sulphur trioxide;

Question 45. Give an example of a polynuclear hydrocarbon.
Answer: Anthracene

Question 46. Which compound other than anhydrous AlCl₃ can be used for the ethylation of benzene?
Answer: FeCl₃

Question 47. What is gamm exane? Mention its use.
Answer: BHC (Benzene hexachloride); as an insecticide

Question 48. What is the electrophile involved in the nitration reaction?
Answer: NO₂

Question 49. Name the products obtained on pyrolysis of propane.
Answer: Propene, ethene, methane, and H₂

Question 50. Which compound out of 1-butene, 1-butyne, and 2-butyne is most acidic?
Answer: 1-butyne is the most acidic.

Question 51. Write the name of the compound obtained when n-heptane is subjected to aromatization
Answer: Toluene (C₆H₅—CH₃).

Question 52. Which alkane cannot be prepared by Kolbe’s method?
Answer: Methane (CH₄).

Question 54. Write the names of the compounds obtained on ozonolysis of o-xylene.
Answer: Glyoxal, methyl glyoxal, and dimethyl glyoxal

Question 55. What is lindane?
Answer: Benzene hexachloride (BHC), C₆H₆Cl₆.

Question 56. What is picric acid?
Answer:  2,4,6-trinitrophenol is known as picric acid

Question 57.  What is the name of the compound obtained when benzene is oxidized by air (02) in the presence of a V205 catalyst heated at 500°C?
Answer: Maleic anhydride

Question 58. Which group out of -NO, and -CgHg is an o-/p directing group and which one is an o-/p-directing group?
Answer: NO₂→m -directing; —C₆H₅→o-/p -directing

Question 59.  Which will undergo nitration at a faster rate: C₆H₆ or C₆H₅Cl?
Answer: C₆H₆ undergoes nitration at a comparatively faster rate

Question 60. Name a group that is o -/p -directing but is also a deactivating group.
Answer: Chloro(-Cl)

Question 61. A hydrocarbon on ozonolysis produces ethanal and methanal. 
Answer:  CH₃CH =CH₂

Question 62. Mention the product:
Answer: CH₃CHO

Question 63. Write the structure of an organic compound which reacts with water to yield methanal and hydrogen peroxide
Answer:

Question 64.  Benzene reacts with CH₃COCl in the presence of anhydrous AlCl₃ to form (an organic compound).
Answer: Acetophenone.

Question 65. Which reagent can be used for the following conversion?  HC≡CH→HC=CH₂
Answer: H₂,Pd-CaCO₃/Pb(OAc)₂ (Lindler’s catalyst)

NCERT Solutions For Class 11 Chemistry Chapter 13 Hydrocarbons Fill In The Blanks

Question 1. The formula of marsh gas is _______________
Answer: CH₄

Question 2.  _______________ are called paraffins.
Answer: Alkanes

Question 3. Beryllium carbide yields _______________
Answer: CH₄

Question 4. Dutch oil is _______________
Answer: 1,2-dichloroethane;

Question 5. Wurtz reaction is suitable for the preparation of _______________alkanes.
Answer: Symmetrical

Question 6. CHgCOCHg undergoes Clemmensen reduction to yield _______________
Answer: Propane

Question 7.___________ can be identified by Schryver’s colour test
Answer: CH

Question 8. Peroxide effect is applicable only for _______________
Answer: HBr

Question 9. _______________ is obtained when. a solution of sodium butanoate is electrolyzed
Answer: n-hexane

Question 10. Isobutylmagnesium bromide reacts with water to form _______________
Answer: Isobutane

Question 11. _______________ on ozonolysis produces formaldehyde and acetaldehyde.
Answer: Propene

Question 12. _______________ is obtained as the major product when 2- butanol is dehydrated.
Answer: But 2 ene

Question Benzene is a polymer of _______________
Answer: Acetylene

Question 14. The simplest hydrocarbon which reacts with ammoniacal silver nitrate to produce a white precipitate is _________
Answer: Acetylene

Question 15. _______________ is obtained when 2-butyne is passed through a mixture of 20% H₂SO₄ and 1% H₂SO₄
Answer: 2 – butanone

Question 16. Hexamethylbenzene is the trimer of _______________
Answer: 2 butyne

Question 17. When a mixture of _________ and Ag – powder is heated ________________ is obtained as the product
Answer: Chloroform, acetylene

Question 18. The values of boiling and melting points of alkadienes are _ than the corresponding alkanes and alkenes containing a same number of carbon atoms.
Answer: Higher

Question 19. Ozonolysis of acetylene forms _______________
Answer: Glyoxal

Question 20. Two molecules of HBr react with acetylene to form _______________
Answer: 1,1 dibromomoethane

Question 21. If an alkene forms only one type of carbonyl compound on ozonolysis, then it can be concluded that the alkene is _______________
Answer: Symmetrical

Question 22. C_xH_y _______________ xCO₂ + + y/2 H₂O Heat
Answer: \(\left(x+\frac{y}{4}\right) \mathrm{O}_2\)

Question 23. The number of isomeric tribromobenze is _______________
Answer: Three

Question 24. 1,3,5-trinitrobenzene is an_ compound. _______________
Answer: Explosive

Question 25. The resonance-stabilised carbocation formed in the first step of the electrophilic substitution reaction is called _______________
Answer: Sigma complex

Question 26. _______________ of benzene is carried out by using N⁺O₄ BF^–₄ salt.
Answer: Nitration

Question 27. When benzene is oxidized by atmospheric oxygen in the presence of V₂O₅ at high temperature, _______________ is obtained.
Answer: Maleic anhydride

Question 28. The product obtained due to Birch reduction of benzene when subjected to ozonolysis forms only _______________
Answer: Propanediol

Question 29. —COOH is a/an ______________ Group but COO is an __________ group
Answer: Deactivating, activating;

Question 30. NH₂ group _______________ electron density at ortho-/para positions of the rin
Answer: Increases;

Question 31.  —NO₂ group ______________ electron density at the meta position of the ring
Answer: Decreases

Question 32. C —C bond lengths of benzene are _________________
Answer: Equivalent

Question 33. Fill in the blank __________(organic compound) is obtained when an aqueous solution of potassium succinate is electrolyzed.
Answer: Ethylene