Chemistry important Notes - Class 11

 Page 1


 1
CHEMISTRY 
 
CHAPTER- HYDROCARBONS (I PUC) 
 
One mark questions 
 
1. What type of structural isomerism is shown by alkanes? 
2.  Which metal is used in Wurtz reaction?   
3. What happens when isopropyl bromide is subjected to Wurtz reaction? 
4.   What is the nature of mechanism of halogenation of alkanes?   
5. Which conformation of ethane is most stable? 
6. Can propane show chain isomerism? 
7. Why are alkenes reactive in nature? 
8. What is the state of hybridization of carbon atoms in ethene? 
9. Which of the following show geometrical isomerism? 
CHCl = CHCl;      CH
2
 = CCl
2
 ;    CCl
2
 = CHCl 
10. Name the halogen used o test unsaturation in a hydrocarbon? 
11. Is peroxide effect applicable addition of HCl to propene? Give reason. 
12. What is Bayer’s reagent? 
13. What is Lindlar’s catalyst? 
14. Name the reaction which locates the position of the double bond? 
15. Give  the tests to show that the given compound is an unsaturated compound. 
16. Why  alkynes does not show geometrical isomerism? 
17. What happens when ethyne is hydrated with dilute solution of HgSO
4
 and H
2
SO
4
? 
18. Name the product formed when vapours of ethyne are passed through HCl 
solution? 
      19. Name the product when ethyne is reduced with Na in liquid ammonia? 
      20.  What happens when vapours of ethyne are passed into red hot iron? 
      21. What is the nature of structure of benzene? 
      22.  Why does benzene resist addition reactions? 
      23.  Which catalyst is used in Friedel,s craft reaction? 
      24.  Name two ortho and two meta directing groups in benzene? 
      25.  What is the nature of substitution in benzene? 
      26.  Who gave the present cyclic structure of benzene? 
      27.  Which electrophile is formed during nitration of benzene? 
      28. What does LNG stand for?  
      29.  Which hydrocarbon is main constitutent of CNG? 
              
  
Two mark questions 
 
      1. What is cracking / pyrolysis? 
      2. Write a short note on isomerization of alkanes? 
      3.  Identify the products X and Y of the following reactions: 
     Y       Na +NH
3
, heat              but-2-yne    H
2
/ Pd/BaSO
4
, Heat         X 
 
Page 2


 1
CHEMISTRY 
 
CHAPTER- HYDROCARBONS (I PUC) 
 
One mark questions 
 
1. What type of structural isomerism is shown by alkanes? 
2.  Which metal is used in Wurtz reaction?   
3. What happens when isopropyl bromide is subjected to Wurtz reaction? 
4.   What is the nature of mechanism of halogenation of alkanes?   
5. Which conformation of ethane is most stable? 
6. Can propane show chain isomerism? 
7. Why are alkenes reactive in nature? 
8. What is the state of hybridization of carbon atoms in ethene? 
9. Which of the following show geometrical isomerism? 
CHCl = CHCl;      CH
2
 = CCl
2
 ;    CCl
2
 = CHCl 
10. Name the halogen used o test unsaturation in a hydrocarbon? 
11. Is peroxide effect applicable addition of HCl to propene? Give reason. 
12. What is Bayer’s reagent? 
13. What is Lindlar’s catalyst? 
14. Name the reaction which locates the position of the double bond? 
15. Give  the tests to show that the given compound is an unsaturated compound. 
16. Why  alkynes does not show geometrical isomerism? 
17. What happens when ethyne is hydrated with dilute solution of HgSO
4
 and H
2
SO
4
? 
18. Name the product formed when vapours of ethyne are passed through HCl 
solution? 
      19. Name the product when ethyne is reduced with Na in liquid ammonia? 
      20.  What happens when vapours of ethyne are passed into red hot iron? 
      21. What is the nature of structure of benzene? 
      22.  Why does benzene resist addition reactions? 
      23.  Which catalyst is used in Friedel,s craft reaction? 
      24.  Name two ortho and two meta directing groups in benzene? 
      25.  What is the nature of substitution in benzene? 
      26.  Who gave the present cyclic structure of benzene? 
      27.  Which electrophile is formed during nitration of benzene? 
      28. What does LNG stand for?  
      29.  Which hydrocarbon is main constitutent of CNG? 
              
  
Two mark questions 
 
      1. What is cracking / pyrolysis? 
      2. Write a short note on isomerization of alkanes? 
      3.  Identify the products X and Y of the following reactions: 
     Y       Na +NH
3
, heat              but-2-yne    H
2
/ Pd/BaSO
4
, Heat         X 
 
 2
      4.  How will you prepare benzene from sodium benzoate? 
     5. What happens when benzene reacts with acetyl chloride in presence of AlCl
3
.  
        Represent in form of chemical reaction         . 
 
 
 
6.  Write the conditions necessary for geometrical isomerism 
7.  Which one is more polar, cis-but-2-ene or trans-but-2-ene and why? 
8.  Write the name of ozonolysis products of but-1-ene. 
9. What happens when alk.KMnO4 is added to ethene? Write the reaction and the use of 
this reaction. 
10. How is acetylene prepared on commercial scale? 
11. Name the functional group of the compound prepared by reaction of propyne with 
water in presence of mercuric salt and sulphuric acid. 
12.  State Markovnikov's rule. 
13.  Name the acid whose sodium salt is required for the preparation of propane? Write 
chemical equation for the reaction. 
14.  Explain Wurtz reaction with an example. Where is it used? 
15.  Define decarboxylation with an example. 
16.  Name the type of reactions which alkanes undergo. Give one example also. 
17. Define conformation. 
18.  What happens when ethanol is heated with conc.H2SO4? 
19. Define hydrogenation. 
20. Draw the Newman’s projection of ethane. 
21. Benzene despite having 3 double bonds is exceptionally stable. Explain. 
22. Benzene undergoes electrophilic substitution reactions easily and nucleophilic     
substitutions with difficulty. Explain. 
 23. List the names of Lewis acid other than anhydrous aluminium chloride which can   
be used during ethylation of benzene. 
24. Define hydrocarbons. 
25. What do you understand by torsional angle? Which of the conformations of ethane 
has the maximum and the minimum torsional strain? 
26. What are the drawbacks of kekule’s structure of benzene? 
27. Draw the sawhorse  projections of ethane 
28. Which is more acidic among the following compounds, benzene, n-hexane and 
ethyne Arrange them in the decreasing order of acidic behaviour. Also give reason for  
this behaviour. 
 
 
Three or four mark questions 
 
1) An alkene ‘A’ on ozonlysis gives a mixture of ethanal and pentan-3-one. Write 
the structureand IUPAC name of alkene ‘A’. 
2)  Out of benzene, m–dinitrobenzene and toluene which will undergo nitration 
most easily and why? 
Page 3


 1
CHEMISTRY 
 
CHAPTER- HYDROCARBONS (I PUC) 
 
One mark questions 
 
1. What type of structural isomerism is shown by alkanes? 
2.  Which metal is used in Wurtz reaction?   
3. What happens when isopropyl bromide is subjected to Wurtz reaction? 
4.   What is the nature of mechanism of halogenation of alkanes?   
5. Which conformation of ethane is most stable? 
6. Can propane show chain isomerism? 
7. Why are alkenes reactive in nature? 
8. What is the state of hybridization of carbon atoms in ethene? 
9. Which of the following show geometrical isomerism? 
CHCl = CHCl;      CH
2
 = CCl
2
 ;    CCl
2
 = CHCl 
10. Name the halogen used o test unsaturation in a hydrocarbon? 
11. Is peroxide effect applicable addition of HCl to propene? Give reason. 
12. What is Bayer’s reagent? 
13. What is Lindlar’s catalyst? 
14. Name the reaction which locates the position of the double bond? 
15. Give  the tests to show that the given compound is an unsaturated compound. 
16. Why  alkynes does not show geometrical isomerism? 
17. What happens when ethyne is hydrated with dilute solution of HgSO
4
 and H
2
SO
4
? 
18. Name the product formed when vapours of ethyne are passed through HCl 
solution? 
      19. Name the product when ethyne is reduced with Na in liquid ammonia? 
      20.  What happens when vapours of ethyne are passed into red hot iron? 
      21. What is the nature of structure of benzene? 
      22.  Why does benzene resist addition reactions? 
      23.  Which catalyst is used in Friedel,s craft reaction? 
      24.  Name two ortho and two meta directing groups in benzene? 
      25.  What is the nature of substitution in benzene? 
      26.  Who gave the present cyclic structure of benzene? 
      27.  Which electrophile is formed during nitration of benzene? 
      28. What does LNG stand for?  
      29.  Which hydrocarbon is main constitutent of CNG? 
              
  
Two mark questions 
 
      1. What is cracking / pyrolysis? 
      2. Write a short note on isomerization of alkanes? 
      3.  Identify the products X and Y of the following reactions: 
     Y       Na +NH
3
, heat              but-2-yne    H
2
/ Pd/BaSO
4
, Heat         X 
 
 2
      4.  How will you prepare benzene from sodium benzoate? 
     5. What happens when benzene reacts with acetyl chloride in presence of AlCl
3
.  
        Represent in form of chemical reaction         . 
 
 
 
6.  Write the conditions necessary for geometrical isomerism 
7.  Which one is more polar, cis-but-2-ene or trans-but-2-ene and why? 
8.  Write the name of ozonolysis products of but-1-ene. 
9. What happens when alk.KMnO4 is added to ethene? Write the reaction and the use of 
this reaction. 
10. How is acetylene prepared on commercial scale? 
11. Name the functional group of the compound prepared by reaction of propyne with 
water in presence of mercuric salt and sulphuric acid. 
12.  State Markovnikov's rule. 
13.  Name the acid whose sodium salt is required for the preparation of propane? Write 
chemical equation for the reaction. 
14.  Explain Wurtz reaction with an example. Where is it used? 
15.  Define decarboxylation with an example. 
16.  Name the type of reactions which alkanes undergo. Give one example also. 
17. Define conformation. 
18.  What happens when ethanol is heated with conc.H2SO4? 
19. Define hydrogenation. 
20. Draw the Newman’s projection of ethane. 
21. Benzene despite having 3 double bonds is exceptionally stable. Explain. 
22. Benzene undergoes electrophilic substitution reactions easily and nucleophilic     
substitutions with difficulty. Explain. 
 23. List the names of Lewis acid other than anhydrous aluminium chloride which can   
be used during ethylation of benzene. 
24. Define hydrocarbons. 
25. What do you understand by torsional angle? Which of the conformations of ethane 
has the maximum and the minimum torsional strain? 
26. What are the drawbacks of kekule’s structure of benzene? 
27. Draw the sawhorse  projections of ethane 
28. Which is more acidic among the following compounds, benzene, n-hexane and 
ethyne Arrange them in the decreasing order of acidic behaviour. Also give reason for  
this behaviour. 
 
 
Three or four mark questions 
 
1) An alkene ‘A’ on ozonlysis gives a mixture of ethanal and pentan-3-one. Write 
the structureand IUPAC name of alkene ‘A’. 
2)  Out of benzene, m–dinitrobenzene and toluene which will undergo nitration 
most easily and why? 
 3
3) Why is Wurtz reaction not preferred for the preparation of alkanes containing 
odd number of carbon atoms? Illustrate your answer by taking one example. 
            4) State Huckel’s rule. Draw the structure of Pyridine and Furan. Are these  
                aromatic? 
            5) Explain the mechanism involved in the chlorination of methane.  
            6) Explain whether the following systems are aromatic or not? 
                   (i)                (ii)     (iii)      
          7)  Write IUPAC names of the following compounds: 
            (i)          
             (ii)  
             (iii)  
             (iv)     
 8) Addition of HBr to propene yields 2-bromopropane, while in the presence of    
       benzoyl peroxide, the same reaction yields 1-bromopropane. Explain and give    
       mechanism. 
 
  9) Write chemical reactions for the following conversions: 
(i) Phenol to benzene 
(ii) Benzene to ethyl benzene 
 
10) How do you convert the following? 
(i)  Benzene to p-nitrotoulene  
(ii)  Benzene to acetophenone  
(iii) Benzene to m-chloronitrobenzene 
 11) Discuss the orbital structure of benzene. 
Page 4


 1
CHEMISTRY 
 
CHAPTER- HYDROCARBONS (I PUC) 
 
One mark questions 
 
1. What type of structural isomerism is shown by alkanes? 
2.  Which metal is used in Wurtz reaction?   
3. What happens when isopropyl bromide is subjected to Wurtz reaction? 
4.   What is the nature of mechanism of halogenation of alkanes?   
5. Which conformation of ethane is most stable? 
6. Can propane show chain isomerism? 
7. Why are alkenes reactive in nature? 
8. What is the state of hybridization of carbon atoms in ethene? 
9. Which of the following show geometrical isomerism? 
CHCl = CHCl;      CH
2
 = CCl
2
 ;    CCl
2
 = CHCl 
10. Name the halogen used o test unsaturation in a hydrocarbon? 
11. Is peroxide effect applicable addition of HCl to propene? Give reason. 
12. What is Bayer’s reagent? 
13. What is Lindlar’s catalyst? 
14. Name the reaction which locates the position of the double bond? 
15. Give  the tests to show that the given compound is an unsaturated compound. 
16. Why  alkynes does not show geometrical isomerism? 
17. What happens when ethyne is hydrated with dilute solution of HgSO
4
 and H
2
SO
4
? 
18. Name the product formed when vapours of ethyne are passed through HCl 
solution? 
      19. Name the product when ethyne is reduced with Na in liquid ammonia? 
      20.  What happens when vapours of ethyne are passed into red hot iron? 
      21. What is the nature of structure of benzene? 
      22.  Why does benzene resist addition reactions? 
      23.  Which catalyst is used in Friedel,s craft reaction? 
      24.  Name two ortho and two meta directing groups in benzene? 
      25.  What is the nature of substitution in benzene? 
      26.  Who gave the present cyclic structure of benzene? 
      27.  Which electrophile is formed during nitration of benzene? 
      28. What does LNG stand for?  
      29.  Which hydrocarbon is main constitutent of CNG? 
              
  
Two mark questions 
 
      1. What is cracking / pyrolysis? 
      2. Write a short note on isomerization of alkanes? 
      3.  Identify the products X and Y of the following reactions: 
     Y       Na +NH
3
, heat              but-2-yne    H
2
/ Pd/BaSO
4
, Heat         X 
 
 2
      4.  How will you prepare benzene from sodium benzoate? 
     5. What happens when benzene reacts with acetyl chloride in presence of AlCl
3
.  
        Represent in form of chemical reaction         . 
 
 
 
6.  Write the conditions necessary for geometrical isomerism 
7.  Which one is more polar, cis-but-2-ene or trans-but-2-ene and why? 
8.  Write the name of ozonolysis products of but-1-ene. 
9. What happens when alk.KMnO4 is added to ethene? Write the reaction and the use of 
this reaction. 
10. How is acetylene prepared on commercial scale? 
11. Name the functional group of the compound prepared by reaction of propyne with 
water in presence of mercuric salt and sulphuric acid. 
12.  State Markovnikov's rule. 
13.  Name the acid whose sodium salt is required for the preparation of propane? Write 
chemical equation for the reaction. 
14.  Explain Wurtz reaction with an example. Where is it used? 
15.  Define decarboxylation with an example. 
16.  Name the type of reactions which alkanes undergo. Give one example also. 
17. Define conformation. 
18.  What happens when ethanol is heated with conc.H2SO4? 
19. Define hydrogenation. 
20. Draw the Newman’s projection of ethane. 
21. Benzene despite having 3 double bonds is exceptionally stable. Explain. 
22. Benzene undergoes electrophilic substitution reactions easily and nucleophilic     
substitutions with difficulty. Explain. 
 23. List the names of Lewis acid other than anhydrous aluminium chloride which can   
be used during ethylation of benzene. 
24. Define hydrocarbons. 
25. What do you understand by torsional angle? Which of the conformations of ethane 
has the maximum and the minimum torsional strain? 
26. What are the drawbacks of kekule’s structure of benzene? 
27. Draw the sawhorse  projections of ethane 
28. Which is more acidic among the following compounds, benzene, n-hexane and 
ethyne Arrange them in the decreasing order of acidic behaviour. Also give reason for  
this behaviour. 
 
 
Three or four mark questions 
 
1) An alkene ‘A’ on ozonlysis gives a mixture of ethanal and pentan-3-one. Write 
the structureand IUPAC name of alkene ‘A’. 
2)  Out of benzene, m–dinitrobenzene and toluene which will undergo nitration 
most easily and why? 
 3
3) Why is Wurtz reaction not preferred for the preparation of alkanes containing 
odd number of carbon atoms? Illustrate your answer by taking one example. 
            4) State Huckel’s rule. Draw the structure of Pyridine and Furan. Are these  
                aromatic? 
            5) Explain the mechanism involved in the chlorination of methane.  
            6) Explain whether the following systems are aromatic or not? 
                   (i)                (ii)     (iii)      
          7)  Write IUPAC names of the following compounds: 
            (i)          
             (ii)  
             (iii)  
             (iv)     
 8) Addition of HBr to propene yields 2-bromopropane, while in the presence of    
       benzoyl peroxide, the same reaction yields 1-bromopropane. Explain and give    
       mechanism. 
 
  9) Write chemical reactions for the following conversions: 
(i) Phenol to benzene 
(ii) Benzene to ethyl benzene 
 
10) How do you convert the following? 
(i)  Benzene to p-nitrotoulene  
(ii)  Benzene to acetophenone  
(iii) Benzene to m-chloronitrobenzene 
 11) Discuss the orbital structure of benzene. 
 4
CHEMISTRY 
 
CHAPTER- HYDROCARBONS (I PUC) 
 
 
Answers : One mark questions: 
 
1) Chain isomerism 
2) Sodium 
3)  2,3-dimethyl butane 
4) Free radical mechanism 
5) Staggered conformation 
6) No 
7) Due to the presence of  pi bond in carbon to carbon double bond 
8) sp
2
 hybridisation 
9) CHCl = CHCl 
10) Bromine 
11) No. Free radical is not formed due to high bond dissociation energy of HCl 
12) Dilute alkaline potassium permanganate solution. 
13) Pd supported over barium sulphate or calcium carbonate  poisoned with   
            quinoline or sulphur. 
14)  Ozonolysis 
15)      a.  Bayer’s test 
                 b.  Bromination 
16)  As they are linear in nature. 
17)  Ethanal is formed. 
18)  1,1-dichloroethane 
19) Trans-2-butene 
20) Benzene. 
21) Planar 
22) Due to delocalization of pi electron charge. 
23) Anhydrous aluminium chloride 
24) Ortho directing groups  --   OH, NH
2
 
Page 5


 1
CHEMISTRY 
 
CHAPTER- HYDROCARBONS (I PUC) 
 
One mark questions 
 
1. What type of structural isomerism is shown by alkanes? 
2.  Which metal is used in Wurtz reaction?   
3. What happens when isopropyl bromide is subjected to Wurtz reaction? 
4.   What is the nature of mechanism of halogenation of alkanes?   
5. Which conformation of ethane is most stable? 
6. Can propane show chain isomerism? 
7. Why are alkenes reactive in nature? 
8. What is the state of hybridization of carbon atoms in ethene? 
9. Which of the following show geometrical isomerism? 
CHCl = CHCl;      CH
2
 = CCl
2
 ;    CCl
2
 = CHCl 
10. Name the halogen used o test unsaturation in a hydrocarbon? 
11. Is peroxide effect applicable addition of HCl to propene? Give reason. 
12. What is Bayer’s reagent? 
13. What is Lindlar’s catalyst? 
14. Name the reaction which locates the position of the double bond? 
15. Give  the tests to show that the given compound is an unsaturated compound. 
16. Why  alkynes does not show geometrical isomerism? 
17. What happens when ethyne is hydrated with dilute solution of HgSO
4
 and H
2
SO
4
? 
18. Name the product formed when vapours of ethyne are passed through HCl 
solution? 
      19. Name the product when ethyne is reduced with Na in liquid ammonia? 
      20.  What happens when vapours of ethyne are passed into red hot iron? 
      21. What is the nature of structure of benzene? 
      22.  Why does benzene resist addition reactions? 
      23.  Which catalyst is used in Friedel,s craft reaction? 
      24.  Name two ortho and two meta directing groups in benzene? 
      25.  What is the nature of substitution in benzene? 
      26.  Who gave the present cyclic structure of benzene? 
      27.  Which electrophile is formed during nitration of benzene? 
      28. What does LNG stand for?  
      29.  Which hydrocarbon is main constitutent of CNG? 
              
  
Two mark questions 
 
      1. What is cracking / pyrolysis? 
      2. Write a short note on isomerization of alkanes? 
      3.  Identify the products X and Y of the following reactions: 
     Y       Na +NH
3
, heat              but-2-yne    H
2
/ Pd/BaSO
4
, Heat         X 
 
 2
      4.  How will you prepare benzene from sodium benzoate? 
     5. What happens when benzene reacts with acetyl chloride in presence of AlCl
3
.  
        Represent in form of chemical reaction         . 
 
 
 
6.  Write the conditions necessary for geometrical isomerism 
7.  Which one is more polar, cis-but-2-ene or trans-but-2-ene and why? 
8.  Write the name of ozonolysis products of but-1-ene. 
9. What happens when alk.KMnO4 is added to ethene? Write the reaction and the use of 
this reaction. 
10. How is acetylene prepared on commercial scale? 
11. Name the functional group of the compound prepared by reaction of propyne with 
water in presence of mercuric salt and sulphuric acid. 
12.  State Markovnikov's rule. 
13.  Name the acid whose sodium salt is required for the preparation of propane? Write 
chemical equation for the reaction. 
14.  Explain Wurtz reaction with an example. Where is it used? 
15.  Define decarboxylation with an example. 
16.  Name the type of reactions which alkanes undergo. Give one example also. 
17. Define conformation. 
18.  What happens when ethanol is heated with conc.H2SO4? 
19. Define hydrogenation. 
20. Draw the Newman’s projection of ethane. 
21. Benzene despite having 3 double bonds is exceptionally stable. Explain. 
22. Benzene undergoes electrophilic substitution reactions easily and nucleophilic     
substitutions with difficulty. Explain. 
 23. List the names of Lewis acid other than anhydrous aluminium chloride which can   
be used during ethylation of benzene. 
24. Define hydrocarbons. 
25. What do you understand by torsional angle? Which of the conformations of ethane 
has the maximum and the minimum torsional strain? 
26. What are the drawbacks of kekule’s structure of benzene? 
27. Draw the sawhorse  projections of ethane 
28. Which is more acidic among the following compounds, benzene, n-hexane and 
ethyne Arrange them in the decreasing order of acidic behaviour. Also give reason for  
this behaviour. 
 
 
Three or four mark questions 
 
1) An alkene ‘A’ on ozonlysis gives a mixture of ethanal and pentan-3-one. Write 
the structureand IUPAC name of alkene ‘A’. 
2)  Out of benzene, m–dinitrobenzene and toluene which will undergo nitration 
most easily and why? 
 3
3) Why is Wurtz reaction not preferred for the preparation of alkanes containing 
odd number of carbon atoms? Illustrate your answer by taking one example. 
            4) State Huckel’s rule. Draw the structure of Pyridine and Furan. Are these  
                aromatic? 
            5) Explain the mechanism involved in the chlorination of methane.  
            6) Explain whether the following systems are aromatic or not? 
                   (i)                (ii)     (iii)      
          7)  Write IUPAC names of the following compounds: 
            (i)          
             (ii)  
             (iii)  
             (iv)     
 8) Addition of HBr to propene yields 2-bromopropane, while in the presence of    
       benzoyl peroxide, the same reaction yields 1-bromopropane. Explain and give    
       mechanism. 
 
  9) Write chemical reactions for the following conversions: 
(i) Phenol to benzene 
(ii) Benzene to ethyl benzene 
 
10) How do you convert the following? 
(i)  Benzene to p-nitrotoulene  
(ii)  Benzene to acetophenone  
(iii) Benzene to m-chloronitrobenzene 
 11) Discuss the orbital structure of benzene. 
 4
CHEMISTRY 
 
CHAPTER- HYDROCARBONS (I PUC) 
 
 
Answers : One mark questions: 
 
1) Chain isomerism 
2) Sodium 
3)  2,3-dimethyl butane 
4) Free radical mechanism 
5) Staggered conformation 
6) No 
7) Due to the presence of  pi bond in carbon to carbon double bond 
8) sp
2
 hybridisation 
9) CHCl = CHCl 
10) Bromine 
11) No. Free radical is not formed due to high bond dissociation energy of HCl 
12) Dilute alkaline potassium permanganate solution. 
13) Pd supported over barium sulphate or calcium carbonate  poisoned with   
            quinoline or sulphur. 
14)  Ozonolysis 
15)      a.  Bayer’s test 
                 b.  Bromination 
16)  As they are linear in nature. 
17)  Ethanal is formed. 
18)  1,1-dichloroethane 
19) Trans-2-butene 
20) Benzene. 
21) Planar 
22) Due to delocalization of pi electron charge. 
23) Anhydrous aluminium chloride 
24) Ortho directing groups  --   OH, NH
2
 
 5
             Meta directing groups  ---    CHO, NO
2
 
25) Electrophilic substitution 
26)  Kekule 
27) Nitronium ion 
28)  Liquefied natural gas 
29) Methane. 
 
Answers: Two mark questions 
 
1) The decomposition of higher alkane into a mixture of lower alkanes , alkenes etc    
             by the application of heat is called pyrolysis / cracking. 
 
2) When unbranched alkanes are heated with anhydrous aluminium chloride and          
             hydrogen chloride isomeric branched alkanes are formed. This process is called    
             isomerization 
 
n-butane                   AlCl
3
 / HCl, 570 K          2-methyl-propane 
 
3) X is Cis-but-2-ene  ; Y is trans-but-2-ene 
 
4)                               
 
 
5)