HSS Live Class 10 Chemistry Focus Notes 2021-2022 Unit 6 PDF

Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® FOCUS AREA 2021-22 Chemistry - Class 10-EM Unit 6 * Carbon has very high tendency of catenation (Ability to make bonds with other carbon atoms). * The valency of carbon is 4. *...

Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® FOCUS AREA 2021-22 Chemistry - Class 10-EM Unit 6 * Carbon has very high tendency of catenation (Ability to make bonds with other carbon atoms). * The valency of carbon is 4. * It has the ability to form different types of chemical bonds with other elements. Look at the representation given below. Imagine that hydrogen atoms are added to these structures. Then we will get the following structures. Certain organic compounds and their molecular formulae are given here. Structure of the compound Molecular Formula C2H6 C2H4 C2H2 *What are the characteristics of the compounds given in the table?• They contain carbon and hydrogen only. Hence they are hydrocarbons. There are compounds having single bond, double bond and triple bond between the carbon atoms.The structure of these compounds can also be written in condensed way as CH3 − CH3 , CH2 = CH2 , CH ≡ CH. Such a representation is known as condensed formula. Prepared by Unmesh B , Govt HSS Kilimanoor ,Thiruvananthapuram 99 460 99 800 Page 1  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® FOCUS AREA 2021-22 Chemistry - Class 10-EM Unit 6 ♥♥♥ Alkanes The open chain hydrocarbons having only single bond between the carbon atoms are included in the Alkane category. In alkanes, as all the four valencies of each carbon atom are satisfied by single bonds, they are known as saturated hydrocarbons. 1. ♥♥♥ Complete the following table. Number of Structure of Condensed formula Molecular Carbon Alkanes formula atoms 1 CH4 CH4 2 CH3-CH3 C2H6 3 CH3-CH2-CH3 C3H8 CH3-CH2- CH2-CH3 C4H10 4 5 CH3-CH2- CH2-CH2-CH3 ----------------- 6 ------------------------------------------------- ----------------------------- C6H14 7 ------------------------------------------------ ------------------------------ ----------------- Prepared by Unmesh B , Govt HSS Kilimanoor ,Thiruvananthapuram 99 460 99 800 Page 2  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® FOCUS AREA 2021-22 Chemistry - Class 10-EM Unit 6 2. ♥♥♥ With the help of the table given above, find relationship between the number of atoms of carbon and hydrogen in alkanes. Number of hydrogen atoms = ( 2 x number of carbon atoms ) +2 3. ♥♥♥ If an alkane contains 'n' carbon atoms, how many hydrogen atoms will be there? ( 2 X n ) +2 4. ♥♥♥ If so, can you deduce a general formula for alkanes? CnH2n+2 5. ♥♥♥ Analyse the following compounds CH4 , C2H6,C3H8 ,C4H10 , C5H12 Certain characteristics of these compounds are given below. • They can be represented by a general formula. • Successive members differ by a CH2 group. Members show similarity in chemical properties. There is a regular gradation in their physical properties. A series of such compounds is called a homologous series. 6.♥♥♥ What are unsaturated hydrocarbons? Hydro carbons having one or more double bond or triple bond between carbon atoms are commonly known as unsaturated hydrocarbons. ♥♥♥ Alkenes Hydro carbons having a double bond between any two carbon atoms are considered as Alkenes. 7.♥♥♥ Complete the table given below. No of Structure of the Molecular Carbon atoms Condensed formula Alkene formula 2 CH2=CH2 C2H4 3 CH2=CH-CH3 C3H6 4 CH2=CH-CH2-CH3 C4H8 5 CH2=CH-CH2-CH2-CH3 6 CH2=CH-CH2-CH2-CH2-CH3 Prepared by Unmesh B , Govt HSS Kilimanoor ,Thiruvananthapuram 99 460 99 800 Page 3  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® FOCUS AREA 2021-22 Chemistry - Class 10-EM Unit 6 8.♥♥♥ Analyse the table above and find the number of hydrogen atoms in an alkene with 'n' carbon atoms. 2Xn 9.♥♥♥ If so, can a general formula of alkenes be deduced ? Try to write it. CnH2n Alkenes given in the above table are also members of a homologous series. ♥♥♥ Alkynes Look at the structure of a hydrocarbon carrying a triple bond between two carbon atoms Hydrocarbons having a triple bond between any two carbon atoms are named as alkynes. 10. ♥♥♥ Complete the table given below. No of Structure of the Condensed formula Molecular Carbon Alkyne formula atoms 2 CH≡CH C2H2 3 CH≡C-CH3 C3H4 4 CH≡C-CH2-CH3 C4H6 5 CH≡C-CH2-CH2-CH3 6 CH≡C-CH2-CH2-CH2-CH3 11. ♥♥♥ Analyse the table above and find the number of hydrogen atoms in an alkyne with 'n' carbon atoms. ( 2 X n ) -2 12. ♥♥♥ If so, can a general formula of alkenes be deduced ? Try to write it. CnH2n-2 Alkynes given in the above table are also members of a homologous series. Prepared by Unmesh B , Govt HSS Kilimanoor ,Thiruvananthapuram 99 460 99 800 Page 4  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® FOCUS AREA 2021-22 Chemistry - Class 10-EM Unit 6 ♥♥♥ Nomenclature of hydrocarbons IUPAC has put forward some rules for the naming of organic compounds. While naming hydrocarbons , the following basic points should be considered • 1. Number of carbon atoms • 2. Nature of the chemical bond between the carbon atoms. Word roots are selected based on the number of carbon atoms. Number of carbon atoms Word Root C1 Meth C2 Eth C3 Prop C4 But C5 Pent C6 Hex C7 Hept C8 Oct C9 Non C10 Dec ♥♥♥ Nomenclature of Unbranched Alkanes. Examine the given structural formula, molecular formula and IUPAC names of some alkanes. Structural formula Molecular formula IUPAC name CH4 Methane C2H6 Ethane C3H8 Propane Prepared by Unmesh B , Govt HSS Kilimanoor ,Thiruvananthapuram 99 460 99 800 Page 5  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® FOCUS AREA 2021-22 Chemistry - Class 10-EM Unit 6 ► How are the names derived from the word roots? Alkanes are named by adding the suffix 'ane' along with the word root that denotes the number of carbon atoms. Meth + ane → Methane Eth + ane → Ethane Prop + ane → Propane Word root + ane → Alkane 13. ♥♥♥ Write the IUPAC name of the following alkanes. Condensed formula IUPAC Name CH3-CH2-CH2-CH3 CH3-CH2-CH2-CH2-CH3 CH3-CH2-CH2-CH2-CH2-CH3 CH3-CH2-CH2-CH2-CH2-CH2-CH3 CH3-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3 CH3-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3 Answer: Condensed formula IUPAC Name CH3-CH2-CH2-CH3 Butane CH3-CH2-CH2-CH2-CH3 Pentane CH3-CH2-CH2-CH2-CH2-CH3 Hexane CH3-CH2-CH2-CH2-CH2-CH2-CH3 Heptane CH3-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3 Nonane CH3-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3 Decane 14.♥♥♥ Complete the following table Condensed formula IUPAC Name....................................................................................... Propane...................................................................................... Octane CH3-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3................................ Answer: Condensed formula IUPAC Name CH3-CH2-CH3 Propane CH3-CH2-CH2-CH2-CH2-CH2-CH2-CH3 Octane CH3-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3 Decane Prepared by Unmesh B , Govt HSS Kilimanoor ,Thiruvananthapuram 99 460 99 800 Page 6  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® FOCUS AREA 2021-22 Chemistry - Class 10-EM Unit 6 ♥♥♥ Nomenclature of Branched Hydrocarbons Consider the following compound CH3-CH2-CH-CH3 | CH3 According to the IUPAC rules of nomenclature, the longest chain (with the maximum number of carbon atoms) should be considered as the main chain and the remaining carbon atoms are treated as branches. The position of the branches can be found out by numbering carbon atoms in the main chain. Numbering of the carbon atoms in the chain should be done in such a way that the carbon atom carrying the branch gets the lowest number. Hence the numbering should be done in the following way. After understanding the correct numbering , go through the following points. a) Number of carbon atoms in the main chain :4 b) Word root : But c) Suffix : ane d) Name of the alkyl radical coming as branch : Methyl e) Position of the branch :2 f) IUPAC name : 2-Methyl butane Position number of branch + hyphen + name of radical(branch) + word root + suffix. A hyphen (−) is used to separate numerals and alphabets while writing the IUPAC name. Prepared by Unmesh B , Govt HSS Kilimanoor ,Thiruvananthapuram 99 460 99 800 Page 7  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® FOCUS AREA 2021-22 Chemistry - Class 10-EM Unit 6 15. ♥♥♥ Write IUPAC names of the hydrocarbons given below. Answer: Prepared by Unmesh B , Govt HSS Kilimanoor ,Thiruvananthapuram 99 460 99 800 Page 8  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® FOCUS AREA 2021-22 Chemistry - Class 10-EM Unit 6 More practice questions. 16. ♥♥♥Write the IUPAC names of the following. Number of carbon Position Compound atoms in the Name of branch of IUPAC Name longest Branch chain CH3-CH-CH2-CH3 | CH3 CH3-CH2-CH2-CH-CH3 | CH3 CH3-CH2-CH2-CH2-CH-CH3 | CH3 CH3-CH2-CH2-CH-CH2-CH3 | CH3 CH3-CH2-CH-CH2-CH2-CH3 | CH3 CH3-CH2-CH-CH2-CH2-CH3 | CH2-CH3 CH3-CH2-CH2-CH-CH2-CH3 | CH2 | CH3 While naming a branch it is better to have knowledge about alkyl groups. Alkyl groups are obtained by removing a hydrogen atom from alkanes Alkane Alkyl group Methane Methyl CH4 CH3 - Ethane Ethyl C2H6 C2H5 - or CH3-CH2 - Propane Propyl C3H8 C3H7 - or CH3-CH2 -CH2 - Prepared by Unmesh B , Govt HSS Kilimanoor ,Thiruvananthapuram 99 460 99 800 Page 9  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® FOCUS AREA 2021-22 Chemistry - Class 10-EM Unit 6 Answer: Number of carbon Position Compound atoms in the Name of branch of IUPAC Name longest Branch chain CH3-CH-CH2-CH3 | 4 Methyl 2 2-Methylbutane CH3 CH3-CH2-CH2-CH-CH3 | 5 Methyl 2 2-Methylpentane CH3 CH3-CH2-CH2-CH2-CH-CH3 | 6 Methyl 2 2-Methylhexane CH3 CH3-CH2-CH2-CH-CH2-CH3 | 6 Methyl 3 3-Methylhexane CH3 CH3-CH2-CH-CH2-CH2-CH3 | 6 Methyl 3 3-Methylhexane CH3 CH3-CH2-CH-CH2-CH2-CH3 | 6 Ethyl 3 3-Ethylhexane CH2-CH3 CH3-CH2-CH2-CH-CH2-CH3 | CH2 6 Ethyl 3 3-Ethyl hexane | CH3 17.♥♥♥ Complete the table. IUPAC Name Structural formula 2 – Methyl Propane 3 – Methyl heptane 3 – Ethyl Octane 4– Ethyl Decane Prepared by Unmesh B , Govt HSS Kilimanoor ,Thiruvananthapuram 99 460 99 800 Page 10  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® FOCUS AREA 2021-22 Chemistry - Class 10-EM Unit 6 Answer: IUPAC Name Structural formula 2 – MethylPropane CH3 | CH3-CH-CH3 3 – Methylheptane CH3 | CH3-CH2-CH-CH2-CH2-CH2-CH3 CH2-CH3 3 – Ethyloctane | CH3-CH2-CH-CH2-CH2-CH2-CH2-CH3 CH2-CH3 4– Ethyldecane | CH3-CH2-CH2-CH-CH2-CH2-CH2-CH2-CH2-CH3 Prepared by Unmesh B , Govt HSS Kilimanoor ,Thiruvananthapuram 99 460 99 800 Page 11  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® FOCUS AREA 2021-22 Chemistry - Class 10-EM Unit 6 ♥♥♥Nomenclature of hydrocarbons with more than one branch If the same type of branch is present more than once, as per rule, numbering should be done either from left to right or from right to left so as to get the lowest number for the branch coming first in the longest chain. Prepared by Unmesh B , Govt HSS Kilimanoor ,Thiruvananthapuram 99 460 99 800 Page 12  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® FOCUS AREA 2021-22 Chemistry - Class 10-EM Unit 6 To students... Some compounds are given.Name them your own. Look at the answers after that.If there is a discrepancy with the answer given, please understand the explanation. Compound IUPAC Name Explanation The number of the first branch is 2 when numbered from left to right. The number of the first branch is 4 when the number is given 2,4-Dimethylheptane from right to left. The position number of the first branch should get the smallest possible number Total two branches. The position of the first branch is 2 even if the number 2,4- Dimethylpentane is given from left to right or from right to left The number of the first branch is 3 when numbered from left to right. The number of the first branch is 2 when the number 2,4- Dimethylhexane is given from right to left. The position number of the first branch should get the smallest possible number There are 3 branches in total.The first branch is at the same distance from the two 2,3,5-Trimethylhexane ends So the next branch should be considered and numbered. This branch is marked as If a carbon atom has two identical branches, the number of their position 2,2-Dimethylpropane should be repeated. Prepared by Unmesh B , Govt HSS Kilimanoor ,Thiruvananthapuram 99 460 99 800 Page 13  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® FOCUS AREA 2021-22 Chemistry - Class 10-EM Unit 6 ♥♥♥ Nomenclature of unsaturated Hydrocarbons 18.♥♥♥ Classify and tabulate the following compounds into alkanes, alkenes and alkynes. C5H10 , C6H10 , C2H4 , C5H12 , C6H12 , C7H12 , C10H22 , C4H10 , C4H8 , C4H6 ,C2H6 , C3H6 ,C2H2 , C3H4 C3H8. Answer: Alkane Alkene Alkyne C5H12 C5H10 C6H10 C10H22 C2H4 C7H12 C4H10 C6H12 C4H6 C2H6 C4H8 C2H2 C3H8 C3H6 C3H4 26.Write the structural formula of the compound C2H4 Answer: CH2=CH2 19.♥♥♥ What is the IUPAC name of the compound CH2=CH2 ? ( Hint : Replace the 'ane' in the IUPAC name of the alkane with 'ene'. Alk + ene = alkene) Answer: The IUPAC name of the compound is Ethene. More examples: 20.♥♥♥ What is the IUPAC name of the compound CH3-CH=CH2 ? Answer: Propene. 21.♥♥♥ What is the IUPAC name of the compound CH2=CH-CH2-CH3 ? If your answer is Butene, then ,what is the IUPAC name of CH3-CH=CH-CH3 ? Is it Butene? Look at the difference in the position of the double bond. For unbranched, unsaturated hydrocarbons with four or more carbon atoms, position number of the doubly bonded carbon atom should be indicated. Then , What is the IUPAC name of the compound CH3-CH2-CH=CH2 ? Let's go through this example While numbering the carbon atoms, during IUPAC naming, the carbon atoms linked by double bond should be given the lowest position number. Accordingly, it is in method (1) that the lowest position numbers are given to the doubly bonded carbon atoms. What will be the IUPAC name of the compound then? Answer: But-1-ene Prepared by Unmesh B , Govt HSS Kilimanoor ,Thiruvananthapuram 99 460 99 800 Page 14  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® FOCUS AREA 2021-22 Chemistry - Class 10-EM Unit 6 22.♥♥♥ What is the structure of But-2-ene ? Answer: CH3-CH=CH-CH3 23.♥♥♥.What is the IUPAC name of CH3-CH2 - CH=CH-CH3 ? Answer: Pent-2-ene 24.♥♥♥What is the IUPAC name of CH3-CH=CH-CH2-CH3 ? Answer: Pent-2-ene. For naming alkynes , the same method has to be followed. Alk + yne = Alkyne. 25.♥♥♥ What is the IUPAC name of CH≡CH ? Answer: Ethyne 26.♥♥♥ What is the IUPAC name of CH3-C≡CH ? Answer: Propyne 27.♥♥♥ What is the IUPAC name of CH3-CH2- C≡CH ? Answer: But-1-yne 28.♥♥♥ What is the structure of But-2-yne ? Answer: CH3-C≡C-CH3 29.♥♥♥ What is the structure of Pent-2-yne ? Answer: CH3-CH2-C≡C-CH3 OR CH3-C≡C-CH2 -CH3 Prepared by Unmesh B , Govt HSS Kilimanoor ,Thiruvananthapuram 99 460 99 800 Page 15  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® FOCUS AREA 2021-22 Chemistry - Class 10-EM Unit 6 ♥♥♥ Functional groups. Carbon and hydrogen are not the only elements present in organic compounds. There are other atoms and groups of atoms present in the place of hydrogen atoms in organic compounds. The presence of certain atoms or groups imparts certain characteristic properties to organic compounds. They are called functional groups. Some important functional groups are given below. Sl Functional Structure Name IUPAC Name No group 1 ♥♥♥ -OH Alcohol Alkanol Hydroxyl group 2 ♥♥♥ -O-R Ether Alkoxyalkane Alkoxy group ( R – Alkyl groups like CH3-, CH3-CH2-, CH3-CH2-CH2- or Aryl groups like C6H5- ) 1.♥♥♥ Hydroxyl Group ( - OH) IUPAC Name : Alkane - e + ol → Alkanol 30.♥♥♥ What is the IUPAC name of CH3-OH? Answer: Methane-e+ ol = Methanol 39.♥♥♥ What is the IUPAC name of CH3-CH2-OH? Answer: Ethanol 31.♥♥♥ What is the IUPAC name of CH3 -CH2-CH2-OH? Is it Propanol ? If yes, then , what is the IUPAC name of CH3-CH-CH3 ? | OH CH3 -CH2-CH2-OH is Propan-1-ol CH3-CH-CH3 | is Propan-2-ol OH 32. ♥♥♥What is the IUPAC name of CH3 -CH2-CH2-CH2-OH? Answer : Butan-1-ol 33. ♥♥♥What is the IUPAC name of CH3 -CH-CH2-CH3 ? | OH Answer : Butan-2-ol 34. ♥♥♥ What is the IUPAC name of CH3 -CH2-CH-CH3 ? | OH Answer : Butan-2-ol (The main chain should be numbered from the end nearest to the functional group.) Prepared by Unmesh B , Govt HSS Kilimanoor ,Thiruvananthapuram 99 460 99 800 Page 16  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® FOCUS AREA 2021-22 Chemistry - Class 10-EM Unit 6 35. ♥♥♥ What is the structural difference between CH3 -CH2-CH2-OH and CH3-CH-CH3 ? | OH Answer: The position of functional group is different. or 2.♥♥♥Carboxylic Group Carboxylic acids are compounds containing -COOH group. Look at the IUPAC names of some compounds Compound IUPAC Name H-COOH Methanoic acid CH3-COOH Ethanoic acid CH3-CH2-COOH Propanoic acid CH3-CH2-CH2 -COOH Butanoic acid While writing IUPAC names of these compounds, the name of the main chain is terminated with the suffix 'oic acid'.alkane - e + oic acid Vinegar contains acetic acid ( CH3-COOH).Its IUPAC name is ethanoic acid 3.♥♥♥Halo Group Organic compounds with functional groups fluro (-F), chloro (-Cl ), bromo (-Br ) and iodo (- I ) are called Halo compounds. The method of giving IUPAC names to these compounds is given below. Compound IUPAC name CH3-Cl Chloromethane CH3-CH2-Cl Chloroethane CH3-CH2-CH2-Cl 1-Chloropropane 2,2- Dichlorobutane Cl Cl 2,3- Dichlorobutane Prepared by Unmesh B , Govt HSS Kilimanoor ,Thiruvananthapuram 99 460 99 800 Page 17  Join Telegram Channel: https://t.me/hsslive Downloaded from www.Hsslive.in ® FOCUS AREA 2021-22 Chemistry - Class 10-EM Unit 6 4. ♥♥♥Alkoxy Group (- R-O ) Ethers are compounds with an alkoxy group. IUPAC Name: Alkoxy alkane Examples are given below. Sl No Ether IUPAC name 1 CH3 -O -CH3 Methoxymethane 2 CH3-CH2 -O -CH2-CH3 Ethoxyethane 3 CH3-CH2-CH2-O-CH2-CH2-CH3 Propoxypropane 4 CH3-O-CH2-CH3 Methoxyethane 5 CH3-CH2-O-CH3 Methoxyethane 6 CH3-CH2-O-CH2-CH2-CH3 Ethoxypropane 7 CH3-O-CH2-CH2-CH2 -CH3 Methoxybutane 8 CH3-CH2-O-CH2-CH2-CH3 Ethoxypropane 9 CH3-CH2-CH2-CH2-O-CH2-CH3 Ethoxybutane 10 CH3-CH2-CH2-CH2-O-CH3 Methoxybutane Here among the alkyl radicals on either side of the -O- group , the longest alkyl group is taken as alkane and the other as alkoxy group. Look at the above table one again and verify Prepared by Unmesh B , Govt HSS Kilimanoor ,Thiruvananthapuram 99 460 99 800 Page 18