9. C h p t e r t G l n c e Hydrocrbons - The fundmentl orgnic compounds : All orgnic compounds contin hydrogen long with crbon. They re the fundmentl orgnic compounds lso known s "Prent" compounds. These compounds re known s Hydrocrbons. Sturted nd unsturted hydrocrbons : Hydrocrbons in which the crbon toms re linked to ech other only by single bonds re known s sturted hydrocrbons. Eg. Methne, Ethne, Propne etc. Unsturted hydrocrbons : Hydrocrbons in which crbon toms re linked to ech other by double or triple bonds re known s unsturted hydrocrbons. Hydrocrbons contining only single C - C bonds re clled lknes. Hydrocrbons contining double nd triple bonds between crbon toms re known s lkenes nd lkynes respectively. Functionl groups in orgnic compounds : The tom or group of toms present in the molecule which determines chrcteristics property of orgnic compounds is clled the functionl group. Eg. CH 3 -. (Methyl lcohol). The group is known s the lcoholic functionl group. Homologous series : A group of orgnic compounds contining sme functionl group, which cn be represented by the sme generl formul nd which more or less show similr trends in their properties is known s Homologous series. Nomenclture of orgnic compounds : The ltest nd widely ccepted system for giving systemtic nmes to orgnic compounds is the IUPAC (Interntionl Union of Pure nd Applied Chemists) system. According to IUPAC system ll orgnic compounds re considered s derivtives of sturted hydrocrbons nd re known s Alkenes. Eg. The compound C 2 (ethnol) is nmed s 2 CH 3 1 CH ethne 1 ol. Addition rection : The rection in which two molecules rect to form single product is known s ddition rection. This type of rection occurs only in unsturted compounds where there re double or triple bonds.
SCIENCE & TECHNLGY - S.S.C. 115 Substitution rection : Rections where substitution of one (or more toms) in molecule for nother tom tkes plce re clled substitution rections. Some importnt crbon compounds : ) Ethnol : Ethnol is clled ethyl lcohol or spirit. Ethnol hs formul C 2 nd hs Liner structure CH 3 CH 2. Ethnol is colourless liquid nd hs plesnt odour. b) Ethnoic cid : Commonly known s cetic cid. Ethnoic cid hs the formul C 2 nd hs liner structure CH 3 C. It is wek cid, colourless, corrosive liquid nd pungent smell t ordinry temperture. MCQ's BASED N PRACTICALS MULTIPLE CHICE QUESTINS (MCQ's) (Ech question crries one mrk) Experiment : I. To study the properties of cetic cid (ethnoic cid) : (A) odour (B) solubility in wter (C) effect on litmus (D) rection with sodium bicrbonte 1. Some cetic cid is treted with solid NHC 3. The resulting solution will be : colourless b blue c green d yellow 2. Ethnoic cid : is odourless c hs smell of rotten eggs 3. Acetic cid : turns blue litmus red c is ple yellow in colour d ), b), c) b hs pungent smell d hs smell of lemon b is insoluble in wter 4. Sodium bicrbonte solution is dded to dilute ethnoic cid. It is observed tht : gs is evolved b solid settles t the bottom c the mixture becomes wrm d the colour of the mixture becomes yellow 5. 2ml of ethnoic cid ws tken in ech of the three test tubes A, B, C nd 2ml, 4ml, nd 8ml wter ws dded respectively to them. A cler solution is obtined in : test tube A b test tube B c test tube A nd B d ll the test tubes 6. When cetic cid rects with zinc metl, the gs given out is : H 2 b c C d S 7. When cetic cid rects with ethyl lcohol in presence of nhydrous ZnCl 2, the product formed is : ester b sodium ethoxide c ethnoic cid d methyl lcohol 8. Wht is ethnoic cid which solidifies below 290K known s? ice b solid cetic cid c glcil cetic cid d ethyl cette
116 9. Functionl group of cetic cid is : Unique MCQ's b CH c C d CH 3 10. Spirit is : ethyl lcohol b ethyl chloride c ethyl cette d ester 11. Which of the following is not property of ethnoic cid? it is colourless cid b it hs pungent smell c it is strong cid d ll of these 12. Freezing point of Ethnol is : 114ºC b 78ºC c 100ºC d 114ºC 13. Generl formul of crboxylic cid is : R CH b R C c R d 14. Chemicl formul of Butyl Alcohol is : C 3 b C 4 c CH 3 d C 2 MCQ's BASED N CHAPTER Moderte Level 1. All orgnic compounds contin : crbon nd oxygen b crbon nd nitrogen c hydrogen nd oxygen d crbon nd hydrogen 2. Which llotrophy of crbon is used for cutting glss? dimond b grphite c col d chrcol 3. Formul of cetldehyde is : CH 3 CH = b C 2 c CH d CH 3 CH 2 CH 3 C CH3 3 4. Structure of benzene is : c CH 3 CH = CH CH 3 d 5. CH 3 C CH3 is : dimethyl cid b dimethyl ketone c ethylene d cetldehyde b CH 3 C CH3 R C R
SCIENCE & TECHNLGY - S.S.C. 117 6. The lkne fmily is homologous series nd chrcterized by the generl formul : C n H 2n b C n H 2n 2 c C n H 2n+2 d C n H 2n 4 Elementry Level 1. Number of crbon toms present in pentne : 2 b 3 c 4 d 5 2. Wht is the IUPAC nme of : CH 3 CH 2 CH = CH 2? But 1 ene b But 2 ene c But 1 ne d Pentene 3. Generl formul of lcohol is : C n H 2n b C n H 2n+1 c C n H 2n+1 d C n H 2n+2 1. The IUPAC nme of HCH is : Complex Level methnl b ethnl c propnl d cetldehyde 2. The moleculr formul of butne is : C 4 c C 4 d C 3 3. ne of the following moleculr formul cn represent two orgnic compounds hving different functionl groups. This moleculr formul is : C 5 b C 5 c C 5 d C 5 4. The next homologue of C 3 is : C 2 c C 4 d C 5 H 11 5. The functionl group which lwys occurs in the middle of crbon chin is: ketone b lcohol c cid d ldehyde 6. Which of the following is unsturted compound? C 4 c C 2 d C 5 7. Which of the following is n lkyne? C 2 c C d C 3 8. The number of isomers formed by the hydrocrbon with moleculr formul C 5 is : 2 b 5 c 3 d 4 Mysterious Level 1. Which functionl group do you think cn be present in n orgnic compound hving the moleculr formul C 5? C b CH c d C Hint : C 4 C 2. Which of the following cnnot exhibit isomerism? C 4 b C 5 c C 3 d C 6 Hint : It is not possible to hve different rrngement of toms in propne.
118 3. Which formul represents cyclohexne s well s hexene? Unique MCQ's C 6 b C 6 c C 5 d C 5 Hint : CH 3 CH = CH 2 hexene 4. Which formule represent unsturted hydrocrbon hving triple bond? C 5 b C 7 c C 6 d C 5 Hint : CH 3 C CH 5. ne of the following moleculr formule represents ketone. This formul is : C 5 b C 6 c C 6 d C 6 Hint : Functionl group of Ketone is C MCQ's BASED N PRACTICAL SKILLS Answers 1-2 - b 3-4 - 5 - d 6-7 - 8 - c 9 - c 10-11 - c 12 - d 13 - b 14 - b MCQ's BASED N CHAPTER Moderte Level Elementry Level Complex Level Cyclohexne 1 - d 2-3 - 4-5 - b 6 - c 1 - d 2-3 - b 1-2 - c 3 b 4 - c 5-6 - b 7 b 8 - c Mysterious Level 1-2 - c 3 - b 4-5 - d