Page 3 :
Unit-1, Chemical Substances-Nature and Behaviour, , 1, , Carbon and its Compounds, , Topics Covered, 1.1 Bonding in Carbon–The Covalent Bond and Versatile Nature of Carbon, 1.2 Homologous Series, , C hapter map, , Bonding in Carbon, , Covalent Bond, , Allotropy of Carbon, , Electron Dot Structure, Diamond, , Graphite, , Fullerenes, , Large Number of Carbon Compounds, , Catenation, , Tetravalency, Hydrocarbons, Chains, , Branches, , Rings, , Homologous Series, , in Carbon: The Covalent Bond and Versatile, Topic 1. Bonding, Nature of Carbon, Carbon: Carbon has atomic number 6, mass number 12. It has 6 protons, 6 electrons and 6 neutrons. Its, electronic configurations is 2, 4. It has four valence electrons. It belongs to group 14 and second period of the, periodic table., Organic Compounds: Those compounds which contain carbon essentially alongwith hydrogen and mostly,, oxygen, sulphur, nitrogen, halogen, etc., , Covalent bond: The bond which is formed by equal sharing of electrons is called covalent bond., Covalency of Carbon: Carbon has four valence electrons. It cannot lose 4 electrons because high energy is, needed to remove 4 electrons. It can share four electrons to form four covalent bonds, therefore its covalency, is equal to 4, i.e. it shows tetravalency., , Single Covalent bond: The bond formed by sharing one electron each is called single covalent bond, e.g. the, , following molecules have single bonds.
Page 4 :
H, H H, , Cl Cl, , H–H, (Hydrogen), , Cl–Cl, (Chlorine), , H C H, H, , H O H, , H Cl, H–Cl, (Hydrogen Chloride), , H–O–H, (Water), , H, , H, , H, , C, , C H, , H, , HH HH, , H–C–H, H, (Methane), , H–C–C–H, HH, (Ethane), , Double Covalent bond: When two atoms share two electrons each, double covalent bond is formed., O O , , , , , , O=O, (Oxygen), , Triple covalent bond: When two atoms share three electrons each, triple covalent bond is formed., , Properties of Covalent Compounds:, (i), (ii), (iii), (iv), , They are insoluble in water but soluble in organic solvents., They do not conduct electricity as they do not form ions., They have low melting and boiling points., They exist in solid, liquid as well as in gaseous state., Allotropes: The property due to which one element exist in more than one form, which differ in physical, properties but have similar chemical properties. These forms of element are called allotropes., , Allotropes of Carbon: Diamond, Graphite and Fullerenes are crystalline allotropes of carbon., , 340 pm, , 154 pm, , Structure of diamond, , Structure of graphite, , The structure of C60, (Buckminster, fullerene): Note that the, molecule has the shape of a, soccer ball (football), , Catenation: The property due to which an atom can form stable covalent bond with the atoms of same element., I. Multiple Choice Questions, , Exercise 1.1, , (1 Mark), , Choose the correct answer from the given options., 1. A molecule of ammonia (NH3) has, (a) only single bonds , (b) only double bonds, (c) only triple bonds , (d) two double bonds and one single bond, 2. Which of the following is the correct representation of electron dot structure of nitrogen?, (a), (b), (c), (d), 3. Carbon forms four covalent bonds by sharing its four valence electrons with four univalent atoms, e.g., hydrogen. After the formation of four bonds, carbon attains the electronic configuration of, (a) Helium, (b) Neon, (c) Argon, (d) Krypton
Page 5 :
4. The correct electron dot structure of a water molecule is, (b), (c), (d), (a), 5. The molecular formula of ethene and its electron dot structure is, (a) C2H4,, , , , (b) C2H4,, , (c) C2H2,, , , , (d) C2H6,, , II. Assertion-Reason Type Questions, , (1 Mark), For question numbers 1 and 2 two statements are given-one labeled as Assertion (A) and the other labeled, Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below:, (a) Both ‘A’ and ‘R’ are true and ‘R’ is correct explanation of the assertion., (b) Both ‘A’ and ‘R’ are true but ‘R’ is not correct explanation of the assertion., (c) ‘A’ is true but ‘R’ is false., (d) ‘A’ is false but ‘R’ is true., 1. Assertion: Carbon forms covalent compound with chlorine of formula CCl4., , Reason: Carbon has 4 valence electrons, valency 4, chlorine has 7 valence electrons, valency 1., 2. Assertion: Carbon forms very large number of compounds., , Reason: It is due to property of catenation and tetravalency, , III. Very Short Answer Type Questions, , (1 Mark), , 1. Draw electron dot structure of NH3 molecule. Predict the total no. of bonds around N-atom., , [Delhi 2016], OR, A molecule of ammonia has the formula NH3. Predict the total number of bonds present around nitrogen, atom. , [CBSE 2016], 2. Why covalent compounds are poor conductors of electricity?, [CBSE 2020], 3. What would be the electron dot structure of carbon dioxide which has the formula, CO2?[NCERT], 4. Which element exhibits the property of catenation to maximum extent and why?, [Delhi 2016], 5. State two characteristic features of carbon which when put together give rise to large number of carbon, compounds., 6. Explain why carbon generally forms compounds by covalent bonds or do not form ionic compounds., Or, 4+, Give reason why carbon neither forms C cations nor C4– anions but form covalent compounds which, are bad conductors of electricity and have low melting and boiling points., [Delhi 2013], Or, Carbon has four electrons in its valence shell. How does carbon attain stable configuration?, [Delhi 2015], 7. Why are most carbon compounds poor conductors of electricity?, [CBSE 2018], 8. Define catenation., [CBSE Sample Paper 2019-2020], 9. Covalent compounds have low melting and boiling point. Why?, [CBSE 2020], 10. How are covalent bonds formed?, [CBSE 2020], , IV. Short Answer Type Questions-I , , (2 Marks), , 1. Carbon, group 14 element in the periodic table, is known to form compounds with many elements., Write an example of a compound formed with (i) Chlorine, (ii) Oxygen., [NCERT Exemplar], 2. In electron dot structure, the valence shell electrons are represented by crosses or dots., (i) The atomic number of chlorine is 17. Write its electronic configuration., (ii) Draw the electron dot structure of chlorine molecule., [NCERT Exemplar], 3. Compare the ability of catenation of carbon and silicon. Give reasons., [NCERT Exemplar], 4. Give a test that can be used to confirm the presence of carbon in a compound. With a valency of 4, how, is carbon able to attain noble gas configuration in its compounds?, [CBSE Sample Paper 2020-21], 5. The number of carbon compounds is more than those formed by all other elements put together. Justify, the statement by giving two reasons., [CBSE Sample Paper 2020-21]
Page 6 :
V. Short Answer Type Questions-II , , (3 Marks), , 1. What are covalent compounds? Why are they different from ionic compounds? List their three, characteristic properties., [Delhi 2016], 2. (a) Explain why carbon forms covalent bond? Give two reasons for carbon forming a large number of, compounds., (b) Explain the formation of ammonia molecule., [CBSE Sample Paper 2018-19], 3. Carbon, a member of group 14, forms a large number of carbon compounds estimated to be about three, million. Why is this property not exhibited by other elements of this group? Explain., [CBSE 2020], 4. Atoms of an element contain five electrons in its valence shell. This element is the major component of, air. It exists as a diatomic molecule., (i) Identify the element., (ii) Show the bond formed between two atoms of this element., (iii) Write the nature of bond between the two atoms., 5. (i) Explain the formation of calcium chloride with the help of electron dot structure. (At numbers: Ca, = 20; Cl = 17), (ii) Why do ionic compounds not conduct electricity in solid state but conduct electricity in molten and, aqueous state?., [CBSE Sample Paper 2020-21], , Answers 1.1, I. 1. (a) It has three single bonds and one lone pair., , 2. (d), It has triple bond, , 3. (b) Carbon attains 8 electrons after sharing four electrons and acquire stable configuration of Neon., , 4. (c), , , , 5. (b) C2H4,, , II. 1. (a) Both ‘A’ and ‘R’ are true and ‘R’ is correct explanation of the assertion., , 2. (a) Both ‘A’ and ‘R’ are true and ‘R’ is correct explanation of the assertion., III. 1., , , It has 3 bonds around N-atom., , , 2. It is because covalent compounds do not form ions., , 3., 4. Carbon since it forms strong covalent bond, due to smaller atomic size., , 5. (i) Catenation, (ii) Tetravalency of carbon., , 6. Carbon as 4 valence electrons. It cannot lose 4 electrons because very high amount of energy is needed. It, also cannot gain four electrons because 6 protons cannot hold 10 electrons., It can share four electrons to form four covalent bonds. Covalent compounds do not conduct electricity, because they do not form ions. They have low melting and boiling points due to weak forces of attraction, between molecules., 7. Carbon compounds form covalent bonds/do not dissociate into ions/do not have charged particles (ions)., , 8. The property of self-linking of atoms of an element through covalent bonds in order to form straight, chain, branched chains or cyclic chains of different sizes is called catenation., , 9. It is because they have weak van der Waal’s forces of attraction between molecules therefore have low, melting and boiling points., , 10. Covalent bonds are formed by equal sharing of electrons., 4+, O2–, Cl1– C, C4+, (ii) , 2. (i) Cl (2,8,7) (ii), IV. 1. (i), CCl4, , CO2
Page 7 :
3. Carbon shows catenation property to more extent than silicon. It is because C–C bond is stronger than, Si–Si bond because carbon is smaller in size than silicon., 4. – Burn compound in air/ oxygen; Gas evolved turns lime water milky, – By sharing its four valence electrons with other elements., 5. • Due to self linking ability of carbon/catenation, , • Since carbon has a valency of four it can form bonds with four other atoms of carbon or atoms of, some other mono-valent element., • Due to small size of carbon it forms very strong and (or) stable bonds with other elements, V. 1. Those compounds which are formed by equal sharing of electrons are called covalent compounds., They are different from ionic compounds since ionic compounds are formed by transfer of electrons from, one atom to another., , Properties:, (i) They have low melting and boiling points., (ii) They do not conduct electricity in molten state and in aqueous solution., (iii) They are mostly insoluble in water but soluble in organic solvents except glucose, sugar, urea, ethyl, alcohol, etc., , 2. (a) Carbon has electronic configuration 2, 4. It could gain four electrons forming C-4 anion or lose 4, electrons to form C+4 cation . Both are not possible due to energy considerations. Carbon overcome, this problem by sharing electrons and forming covalent compounds. Two reasons for forming large, number of compounds:, (1) Catenation (2) Tetra valency, (b) Formation of NH3 molecule, Three hydrogen atoms each share their 1 electron with nitrogen to form three covalent bonds and, make an ammonia molecule (NH3)., , 3. Carbon shows the property of catenation., It forms strong covalent bonds with other atoms of carbon forming long straight, branched and closed, chain compounds., Carbon is smallest in size in group 14 with tatravalency, it can form double as well as triple bonds,, therefore, it can show property of catenation to maximum extent and forms 3 million compounds other, elements cannot show property of catenation to this extent due to larger size form weaker covalent bond, and cannot form double or triple bonds., , 4. (i) Nitrogen, , (ii), , (iii) Triple covalent bond, , C2H4 is molecular formula of Ethene, , 5., , Z, Ca – 20, Cl – 17, ××, × Cl ×, ×× ×, Ca + ××, Cl ×, × ××, ×, , (i), , :, , Electronic configuration, 2881, 287, , ×× –, Ca+2 2 × Cl ×, ×× ×, Ca+2 2Cl–, CaCl2, , , (ii) Ionic compounds do not conduct in solid state due to absence of free ions but they conduct electricity, in molten and aqueous state due to presence of free ions.
Page 8 :
Topic 2. Homologous Series, , Isomerism: Those compounds which have same molecular formula but different structural formula are called, isomers. This phenomenon is called isomerism., , Straight Chain Compounds: Those compounds which have carbon atoms linked in a straight chain are, called straight chain compounds, e.g., H H H H, H C C C C H (Butane), H H H H, , Branched Chain Compounds: Those compounds which have carbon atoms linked as branched chains, e.g., H H H, H C C C H is a branched chain compound., H, H, H C H, H, , Saturated Closed Chain Compounds: Compounds having carbon atoms arranged in the form of a ring, e.g., cyclohexane has the formula C6H12. It has single bonds only., HH HH, C C, H, H, C, C, H, H, C C, HHHH, Aromatic, Closed Chain Compounds: If closed chain compounds contain double or triple bonds, they are, called unsaturated closed chain compounds, e.g. Benzene (C6H6). It is also called an aromatic hydrocarbon., , Hydrocarbons: The compounds formed by carbon and hydrogen only are called hydrocarbons., Heteroatoms: In a hydrocarbon chain if one or more hydrogen atoms is replaced by halogens, oxygen, nitrogen, or sulphur, then these atoms replacing hydrogen are called heteroatoms, , Functional groups: These are the atoms or groups of atoms or reactive part of the compound which determines, O, , O, , the properties of organic compounds, e.g. Cl, OH, C H, C OH, etc., The functional group is attached to the carbon chain by replacing one or more hydrogen atoms., , Homologous series: The series of organic compounds having same functional group and similar chemical, properties is called homologous series., Characteristics:, (i), (ii), (iii), (iv), (v), , Each series has a general formula, e.g. alkane has CnH2n+2 as general formula., Each series has same functional group, e.g. alcohols has –OH group., Successive members differ by CH2 unit, e.g. CH4 and C2H6 differ by CH2 unit., Successive members differ by 12 + 2 = 14 u by weight, e.g. CH4 has 16 u, C2H6 has 30 u weight., There is a gradation in physical properties, e.g. there is an increase in boiling point with the added carbon, chain, i.e. with the increase in molecular weight., , General Formula: The formula from which all the members of homologous series can be derived, e.g. CnH2n, is the general formula of alkenes, CnH2n–2 is the general formula of alkynes.
Page 9 :
Exercise 1.2, I. Multiple Choice Questions, , (1 Mark), , Choose the correct answer from the given options., 1. Structural formula of benzene is, , (a), , (b), , (c), , (d), , 2. Which of the following is not a straight chain hydrocarbon?, (a), , (b) H3CCH2CH2CH2CH2CH3, , CH3, |, (c) H2 C − H2 C − H2 C − CH2, |, CH3, , (d), , CH3, CH3, , CH − CH2 − CH2 − CH3, , II. Assertion-Reason Type Questions, (1 Mark), For question numbers 1 and 2 two statements are given-one labeled as Assertion (A) and the other labeled, Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below:, (a) Both ‘A’ and ‘R’ are true and ‘R’ is correct explanation of the assertion., (b) Both ‘A’ and ‘R’ are true but ‘R’ is not correct explanation of the assertion., (c) ‘A’ is true but ‘R’ is false., (d) ‘A’ is false but ‘R’ is true., 1. Assertion: C6H12, C2H4, C4H8 are alkenes and have double bond., , Reason: C3H4 and C5H8 are alkynes and have triple bond., 2. Assertion: Following are the members of a homologous series:, , CH3OH, CH3CH2OH,CH3CH2CH2OH, , Reason: , A series of compounds with same functional group but differing by – CH2– unit is called a, homologous series., [CBSE 2020], III. Very Short Answer Type Questions, , (1 Mark), , 1. An alkene ‘P’ has three carbon atoms and an alcohol ‘Q’ has four carbon atoms. Write the formulae of, P and Q., 2. Write the molecular formula of benzene and state the number of double bonds in its structure. [Delhi, 2013], 3. What is homologous series?, [Delhi 2016], 4. The molecular formula of two members of a homologous series are C3H4 and C6H10. Write the molecular, formula of a member of this family with five carbon atoms in a molecule., 5. Write the general formula of alkenes. Write the name of the simplest alkene., [Delhi 2015], 6. Write the next homologue of each of the following: (i) C2H4, (ii) C4H6[Delhi 2016], 7. Write the structure of an alcohol with three carbon atoms in the molecule. , 8. Write the molecular formula of alcohol derived from butane., [Delhi 2016]
Page 10 :
9. Write the molecular formula of an alkyne containing 10 atoms of hydrogen., 10. Write the name and molecular formula of the fourth member of alkane series. [Delhi 2016], 11. Write the name and formula of second member of homologous series with general formula CnH2n+2, [Delhi 2015], 12. Write the name and formula of second member of homologous series having general formula CnH2n–2., [Delhi 2016], 13. Which of the following organic compounds belong to the same homologous series:, C2H6, C2H6O, C2H6O2, CH4O, 14. The formula of citric acid is shown below:, COOH, |, CH2, |, HO − C − COOH, |, CH2, |, COOH, State the name of —COOH functional group in citric acid., , [Delhi 2014], , 15. The molecular formula of ‘A’ is C10H18 and ‘B’ is C18H36. Name the homologous series to which they, belong.[Delhi 2014], 16. Write the next homologous of CH3CH2OH and HCOOH., 17. Write the molecular formula of first two members of homologous series having functional group Cl., [Delhi 2017], , 18. Write the molecular formula of the 2nd and the 3rd member of the homologous series whose first member, is methane (CH4)., [AI 2017], 19. How many covalent bonds are there in a molecule of ethane (C2H6)?[NCERT], 20. Write the electron dot diagram of ethane (C2H6) molecule., , [Delhi 2011], , 21. Write the number of covalent bonds in propane, C3H8.[Delhi 2016], 22. Write the number of covalent bonds in the molecule of butane (C4H10).[Delhi 2015], 23. State the valency of the carbon atom in (i) an alkane (ii) an alkyne., 24. Name a cyclic unsaturated carbon compound., [CBSE 2020], 25. Which of the following is not observed in a homologous series? Give reason for your choice., , (a) Change in chemical properties, (c) Gradation in physical properties, IV. Short Answer Type Questions-I , , (b) Difference in -CH2 and 14u molecular mass, (d) Same functional group [CBSE Sample Paper 2020-21], (2 Marks), , 1. The general formula of three compounds A, B and C is CnH2n. ‘B’ has the highest boiling point and ‘C’, has the lowest boiling point., (i) Mention the type of compounds A, B and C., (ii) Which of these has minimum number of carbon atoms?, (iii) Name the homologous series to which A, B and C belong , [Delhi 2016], 2. Select alkenes and alkynes from the following:, C2H4, C3H4, C2H2, C4H8 , Write their structural formula also. , [Delhi 2014, 2015], 3. An alkane has molecular weight 86. Write its molecular formula. What will be its physical state?, [HOTS], , V. Short Answer Type Question-II, , (3 Marks), , 1. What is homologous series of carbon compounds? Give an example and list its three characteristics., [CBSE 2019]
Page 11 :
Answers 1.2, I. 1. (c) It has 6 C–C bonds, 6 C–H bonds and three C = C bonds., , 2. (d) It is branched chain hydrocarbon., II. 1. (b) Both ‘A’ and ‘R’ are true but ‘R’ is not correct explanation of the assertion., , 2. (a) Both ‘A’ and ‘R’ are true and ‘R’ is correct explanation of the assertion., III. 1. ‘P’ is CH3–CH=CH2, ‘Q’ is CH3CH2CH2CH2OH, , 2. C6H6, It has three double bonds, H, H, , , H, , H, H, , H, , , 3. It is a series of organic compounds having same functional group and similar chemical properties., , 4. C5H8, , 5. CnH2n, Ethene is simplest alkene., 6. (i) C3H6, (ii) C5H8, H H H, , 7. CH3CH2CH2OH or H C C C OH, H H H, Propan-1-ol, , , 8. C4H9OH or CH3CH2CH2CH2OH (Butan-1-ol), , 9. C6H10 , 10. C4H10, Butane (CH3CH2CH2CH3), , 11. C2H6, Ethane, 12. C3H4, Propyne, , 13. C2H6O (C2H5OH) and CH4O (CH3OH) , 14. Carboxylic acid, , 15. ‘A’ belongs to Alkynes, ‘B’ belongs to Alkenes., , 16. CH3 – CH2 – CH2OH. Propanol and, CH3COOH ethanoic acid, , 17. The general formula of the compounds having – Cl functional group is CnH2n + 1Cl. Its two members, are:, , (i) CH3Cl, , (ii) CH3 – CH2 – Cl, , 18. (i) CH3CH3 (Ethane); where n is 2, (ii) CH3CH2CH3 (Propane); where n is 3, , 19. There are 7 covalent bonds. , H H, , 20., , H C C H, H H, , 21. There are 10 covalent bonds. 22. There are 13 covalent bonds., H H H, H H H H, H C C C H H C C C C H, H H H, 23. (i) Four, (ii) Four, , H H H H, , , 24. Benzene is cyclic unsaturated carbon compound., , H, H, H, , H, H, , H, , 25. (a) It does not occur due to the presence of the same functional group.
Page 12 :
IV. 1. (i) Unsaturated hydrocarbons with double bonds., (ii) ‘C’ has minimum boiling point, so ‘C’ has minimum no. of C-atoms., (iii) Alkene, , 2. C2H4 and C4H8 are alkenes, C3H4 and C2H2 are alkynes., H H H H, H H, | | | |, | |, HC ≡ CH, HC ≡ C − CH 3, H− C = C −H H− C= C− C− C−H, , (C4 H8 ), (C H ), (C3H 4 ), (C2H4 ), | |, 2 2, H H, , 3. C6H14 has molecular weight of 6 × 12 + 14 = 86u., It is in liquid state at room temperature., V. 1. The series of organic compounds having same functional group and similar chemical properties is called, homologous series. For example,, Alkane: CH4 C2H6 C3H6, Methane Ethane Propane, , , Characteristics: • Each successive member differ by CH2 unit., • They have gradation in physical properties., • They have similar chemical properties due to presence of same functional group., , C ase study question, , 1. Water is a simple molecule consisting of one oxygen atom bonded to two different hydrogen atoms. Because, of the higher electronegativity of the oxygen atom, the bonds are polar covalent (polar bonds). The oxygen, atom attracts the shared electrons of the covalent bonds to a significantly greater extent than the hydrogen, atoms. The molecule has a bent structure, the H—O—H bond angle is about 105°., (i) Which of the following statement is true regarding the electronegativity of atoms in water molecule?, (a) Hydrogen is more electronegative than oxygen, (b) Hydrogen is less electronegative than oxygen, (c) Electronegativity is same in Hydrogen and oxygen, (d) Hydrogen and oxygen do no show significant electronegativity in water, (ii) What is the shape of water molecule?, (a) Linear, (b) Trigonal planar, (c) Bent, (d) Octahedral, (iii) Select the correct type of bonding in a water molecule, (a) Ionic Bonding (b) Covalent Bonding (c) Hydrogen Bonding (d) None of these, (iv) The correct electron dot structure of a water molecule is, (b) H O O, (c) H O H, (d) H O O, (a) H O O, (v) The H—O—H bond angle in water molecule is, (a) 109.5°, (b) 180°, (c) 90°, (d) 105.0°, Ans. (i) (b), (ii) (c), (iii) (b), (iv) (c), (v) (d), , Quick revision notes, • Carbon is a versatile element that forms the basis of all living organisms and large number of materials we, use in our daily life., • Carbon shows allotropy. Diamond, graphite, Buckminster fullerene are allotropes of carbon., • Diamond is hard, lustrous and used in jewellery., • Graphite is soft and used as electrode in cells, lead of pencil, lubricants in machines., • Diamond has octahedral structure, graphite has hexagonal structure and fullerenes have football like, structure., • Carbon forms large number of compounds due to the property of catenation.
Page 13 :
•, •, •, •, •, , Covalent bond is formed by equal sharing of electrons between the combining atoms., Carbon can form covalent bond with hydrogen, oxygen, sulphur, nitrogen and halogens., Carbon also form compounds having double and triple bond between carbon atoms., Carbon can form straight chain, branched chain, closed ring compounds., Carbon compounds belong to homologous series which have common functional group and similar properties., , Common Errors, Errors, , Corrections, , • Students write structural formulae of compounds, wrongly., , ☞ Write skeletal formulae of compounds, making, all the carbon atoms having tetravalency, e.g., H H H, H C C C H, , • Students do not write ‘ane’ and ‘ene’ clearly., • Students write chemical reactions wrongly., • Students leave some parts of 3 mark or 5 mark, questions., • Students do not depict electrons properly in, electron dot structures., , • Students write wrong structural formula of, functional group., , H H H, ☞ Write them clearly. You may use block (capital), letters to avoid confusion., ☞ Do lot of practice by writing equations again and, again., ☞ Do not leave any part. Check whether you have, attempted all the parts or not., ☞ Always depict electrons in pair, e.g., , ☞ Write correct structural formula by keeping in, mind carbon always has tetravalency, i.e. form, four covalent bonds., , important Formulae, S.No., , Formula, , Compound, , 1., , CH4, , Methane, , 2., , CH3—CH3, , Ethane, , 3., , CH3—CH2—CH3, , Propane, , 4., , CH3—CH2—CH2—CH3, , Butane, , 5., , CH3—CH—CH3, , 2-methylpropane, , 6., , CH2 CH2, , Ethene, , 7., , CH3—CH CH2, , Propene, , 8., , CH2 CH—CH2—CH3, , But-1-ene, , 9., , CH3—C CH2, , 2-methylpropene, , CH3, , CH3, CH3, 10., , CH3—C—CH3, , 2, 2-dimethylpropane, , CH3, 11., , H—C C—H, , Ethyne
Page 14 :
12., , CH3—C CH, , Propyne, , 13., , HC C—CH2—CH3, , But-1-yne, , 14., , HC C—CH2—CH2—CH3, , Pent-1-yne, , 15., , HC C—CH2—CH2—CH2—CH3, , Hex-1-yne, , 16., , CH3—CH2—Cl, , Chloroethane, , 17., , CH3Cl, , Chloromethane, , 18., , CH2Cl2, , Dichloromethane, , 19., , CHCl3, , Trichloromethane, , 20., , CCl4, , Tetrachloromethane, , 21., , or, , C6H12, , Cyclohexane, , 22., , or, , C6H6, , Benzene, , 23., , CH3OH, , Methanol, , 24., , CH3CH2OH, , Ethanol, , 25., , CH3CH2CH2OH, , Propan-1-ol, , Assignment, I. Multiple Choice Questions, , Total Marks : 20, (1 Mark), , Choose the correct answer from the given options., 1. Which of the following does not belong to the same homologous series?, (a) CH4, (b) C2H6, (c) C3H8, (d) C4H8, 2. Which of the following is the first member of alkene?, (a) CH3, (b) CH2=CH2, (c) CH3–CH=CH2, (d) CH2, 3. How many valence electrons are present in carbon?, (a) 2, (b) 3, (c) 4, (d) 5, 4. Graphite conducts electricity because, (a) it has free carbon atoms, (b) it has free electrons, (c) its one layer can slip over another layer (d) None of these, , II. Assertion-Reason Type Questions, (1 Mark), Note: Use instructions as given in exercises of the chapter., 1. Assertion: H2O has two covalent bonds and two lone pair of electrons., , Reason: CnH2n is the general formula of alkene., 2. Assertion: Carbon has a strong tendency to either lose or gain electrons to attain noble gas configuration., , Reason: Carbon has four electrons in its outermost shell and has tendency to share electrons with, carbon or other elements., III. Very Short Answer Type Questions, , 1. What do you mean by catenation ?, 2. Draw the electron dot structure of propyne., , IV. Short Answer Type Questions-I , , 1. How are covalent bonds formed?, 2. Draw electron dot structure of H2O and NH3 molecule., , V. Short Answer Type Questions-II, , 1. Draw the structures of three allotropes of carbon., , VI. Long Answer Type Questions, , (1 Mark), , (2 Marks), , (3 Marks), (5 Marks), , 1. (i) What is homologous series of carbon compounds? Give an example and list its three characteristics., (ii) Compare the ability of catenation of carbon and silicon.