{"id":3366,"date":"2023-10-05T08:01:21","date_gmt":"2023-10-05T08:01:21","guid":{"rendered":"http:\/\/localhost\/ecole9ja\/?p=3366"},"modified":"2023-10-05T08:03:51","modified_gmt":"2023-10-05T08:03:51","slug":"week-8-ss2-third-term-chemistry-notes","status":"publish","type":"post","link":"https:\/\/ecolebooks.com\/nigeria\/posts\/week-8-ss2-third-term-chemistry-notes\/","title":{"rendered":"Week 8 &#8211; SS2 Third Term Chemistry Notes"},"content":{"rendered":"<p>\u00a0<strong>WEEK EIGHT<br \/>\n<\/strong><strong>TOPIC:ALKYNES <\/strong><br \/>\n\t<strong>CONTENT<br \/>\n<\/strong><\/p>\n<ul>\n<li>Nomenclature\n<\/li>\n<li>Preparation, Properties and Uses\n<\/li>\n<li>\n<div>Aromatic Hydrocarbons: Benzene Structure\n<\/div>\n<ul>\n<li>Preparation,  Properties and Uses\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>\u00a0<strong>NOMENCLATURE<br \/>\n<\/strong>Alkynes are the homologous series of unsaturated hydrocarbon with a general molecular formula C<sub>n<\/sub>H<sub>2n-2<\/sub>.<\/p>\n<p>\u00a0Alkynes show a high degree of unsaturation than alkenes, hence, they are chemically more reactive than the corresponding alkenes or alkanes.<\/p>\n<p>\u00a0They are named by replacing the &#8216;ane&#8217; of alkanes with &#8216;yne&#8217;.<\/p>\n<p>\u00a0<br \/>\n\u00a0Examples<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0H<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th1.png\" alt=\"\"\/><br \/>\n\t\u00a0\u00a0\u00a0\u00a0H \u2013 C  C \u2013 H\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0H  &#8211; C  &#8211; C C- H<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th2.png\" alt=\"\"\/><br \/>\n\t\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0H<br \/>\n\u00a0\u00a0\u00a0\u00a0Ethyne\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0               Prop-1-yne<\/p>\n<p>\u00a0<strong>ETHYNE<br \/>\n<\/strong>Ethyne is the first member of the alkynes series.  It has a molecular formula,<br \/>\nC<sub>2<\/sub>H<sub>2<\/sub>, and a structural formula of HC = CH.<\/p>\n<p>\u00a0<strong>LABORATORY PREPARATION<br \/>\n<\/strong>Ethyne is usually prepared in the laboratory by the action of cold water on calcium carbide.  The reaction is carried out on a heap of sand to prevent the flask from cracking as a result of the large quantity of heat evolved.<\/p>\n<p>\u00a0<strong>Evaluation<\/strong><br \/>\n\t1.\u00a0\u00a0\u00a0\u00a0Write and name all possible structure of C<sub>6<\/sub>H<sub>8<\/sub><br \/>\n\t2.      How can you prepare a few jars of ethyne in the laboratory?<\/p>\n<p>\u00a0<strong>PHYSICAL PROPERTIES<br \/>\n<\/strong>1.\u00a0\u00a0\u00a0\u00a0Ethyne is a colourless gas with a characteristic sweet smell when pure.<br \/>\n2.\u00a0\u00a0\u00a0\u00a0It is only sparingly soluble in water<br \/>\n3.\u00a0\u00a0\u00a0\u00a0It is slightly less dense than air.<br \/>\n4.\u00a0\u00a0\u00a0\u00a0It is unstable and may explode on compression to liquid.<\/p>\n<p>\u00a0<strong>CHEMICAL PROPERTIES<br \/>\n<\/strong>1.\u00a0\u00a0\u00a0\u00a0\u00a0Combustion:  It undergoes combustion reaction in air to form water and carbon(IV) oxide<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th3.png\" alt=\"\"\/>\u00a0\u00a0\u00a0\u00a02C<sub>2<\/sub>H<sub>2(g)<\/sub> + 5O<sub>2(g)<\/sub>            2H<sub>2<\/sub>O<sub>(l)<\/sub>  +   4CO<sub>2(g)<\/sub><\/p>\n<p>\u00a0NB:  In limited air, it burns with very smoky and luminous flame because of its high carbon content. But in plenty of air and appropriate proportion, it burns with non-luminous very hot flame of about 3000<sup>o<\/sup>C.<\/p>\n<p>\u00a02. \u00a0Addition Reaction:Ethyne undergoes addition reaction to produce unsaturated product with double bonds and then a saturated compound with single bond.<br \/>\na.   \u00a0\u00a0\u00a0\u00a0Reaction with hydrogen in the presence of nickel as catalyst.<\/p>\n<p>\u00a0H HHH\u00a0\u00a0\u00a0\u00a0<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th4.png\" alt=\"\"\/><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th5.png\" alt=\"\"\/><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th6.png\" alt=\"\"\/><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th7.png\" alt=\"\"\/><br \/>\n\t<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th8.png\" alt=\"\"\/><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th9.png\" alt=\"\"\/>\u00a0\u00a0\u00a0\u00a0H- C  C \u2013 H  + H<sub>2 <\/sub>         H \u2013 C = C \u2013 H   H<sub>2(g)<\/sub>         H \u2013 C  &#8211; C  &#8211; H<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th10.png\" alt=\"\"\/><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th11.png\" alt=\"\"\/><br \/>\n\t\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0EtheneH  H    Ethane<br \/>\nb. \u00a0\u00a0\u00a0\u00a0Reaction with halogens:<br \/>\nClClClCl<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th12.png\" alt=\"\"\/><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th13.png\" alt=\"\"\/><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th14.png\" alt=\"\"\/><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th15.png\" alt=\"\"\/><br \/>\n\t<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th16.png\" alt=\"\"\/><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th17.png\" alt=\"\"\/>\u00a0\u00a0\u00a0\u00a0H- CC \u2013 H + Cl<sub>2 <\/sub>\u00a0\u00a0\u00a0\u00a0       H \u2013 C = C \u2013 H         Cl<sub>2<\/sub> H \u2013 C \u2013   C &#8211; H<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th18.png\" alt=\"\"\/><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th19.png\" alt=\"\"\/><br \/>\n\t\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0ClCl<br \/>\n  1,2- dichloroethene1,1,2,2-tetrachloroethane<br \/>\nc.     Reaction with hydrogen halide: Hydrogen halide reacts with ethyne toproduce halo-alkene and further halogenation produce halo-alkane.<br \/>\n\u00a0\u00a0\u00a0                   \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0ClCl\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th20.png\" alt=\"\"\/><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th21.png\" alt=\"\"\/><br \/>\n\t<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th22.png\" alt=\"\"\/><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th23.png\" alt=\"\"\/><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th24.png\" alt=\"\"\/>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0H \u2013 C = C \u2013 H  +HCl       H \u2013 C = C \u2013 H  HCl        H \u2013 C \u2013   C \u2013 H<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th25.png\" alt=\"\"\/><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th26.png\" alt=\"\"\/><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th27.png\" alt=\"\"\/>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<br \/>\nH   ClH   H<br \/>\nChloroethene\u00a0\u00a0\u00a0\u00a0         1,2- dichloro ethane.<\/p>\n<p>\u00a0d.   \u00a0\u00a0\u00a0\u00a0Reaction with water: When ethyne is passed through dilute tetraoxosulphate (vi) acid in the presence of mercury (II) tetraoxosulphate (VI) as catalyst, addition of water takes place to form ethanal.<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0  H       OH\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0H      \u00a0\u00a0\u00a0\u00a0<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th28.png\" alt=\"\"\/><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th29.png\" alt=\"\"\/><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th30.png\" alt=\"\"\/><br \/>\n\t<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th31.png\" alt=\"\"\/><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th32.png\" alt=\"\"\/>\u00a0\u00a0\u00a0\u00a0H-C=C-H   + H<sub>2<\/sub>O       H-  C   =   C \u2013 H          H- C \u2013  C \u2013 H<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th33.png\" alt=\"\"\/><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th34.png\" alt=\"\"\/>\u00a0\u00a0\u00a0\u00a0<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Ethenol\u00a0\u00a0\u00a0\u00a0H    O     Ethanal<\/p>\n<p>\u00a0e.  \u00a0\u00a0\u00a0\u00a0Reaction with acidified KMnO<sub>4<\/sub>: If ethyne is added to acidified KMnO4, it decolourises it. But with alkaline KMnO4, the solution turns to green.<\/p>\n<p>\u00a0<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th35.png\" alt=\"\"\/>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0                        O       O\u00a0\u00a0\u00a0\u00a0<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th36.png\" alt=\"\"\/><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th37.png\" alt=\"\"\/><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th38.png\" alt=\"\"\/>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th39.png\" alt=\"\"\/>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0H \u2013 C = C \u2013 H  +  4[O]        HO \u2013 C  &#8211;  C- OH<br \/>\n                                    KMnO<sub>4<\/sub>Ethanedioic acids<\/p>\n<p>\u00a03. \u00a0\u00a0\u00a0\u00a0Polymerization: In the presence of complex organic \u2013nickel as catalyst ethyne polymerizes to produce benzene.<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th40.png\" alt=\"\"\/>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a03 C<sub>2<\/sub>H<sub>2<\/sub>        C<sub>6<\/sub>H<sub>6<\/sub><br \/>\n\t4. \u00a0\u00a0\u00a0\u00a0Substitution Reaction<br \/>\na. \u00a0\u00a0\u00a0\u00a0Ethyne reacts with ammoniacal solution of copper (1) chloride to form reddish brown solution of copper (I) dicarbide<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th41.png\" alt=\"\"\/>\u00a0\u00a0\u00a0\u00a0C<sub>2<\/sub>H<sub>2<\/sub>  +  2CuCl          Cu<sub>2<\/sub>C<sub>2<\/sub>  +  2HCl\u00a0\u00a0\u00a0\u00a0<br \/>\n b. \u00a0\u00a0\u00a0\u00a0With ammoniacal silver trioxonitrate (v), ethyne forms white silver dicarbide<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th42.png\" alt=\"\"\/>\u00a0\u00a0\u00a0\u00a0C<sub>2<\/sub>H<sub>2<\/sub> + 2AgNO<sub>3<\/sub>Ag<sub>2<\/sub>C<sub>2<\/sub>  + 2HNO<sub>3<\/sub><br \/>\n\t\u00a0\u00a0\u00a0\u00a0These reactions to form dicarbide are used to distinguish ethyne from ethene.<\/p>\n<p>\u00a0<strong>USES OF ETHYNE: <\/strong>Ethyne is<\/p>\n<ol>\n<li>\n<div>Mixed with oxygen to produce oxy ethyne flame for cutting and welding of metals.\n<\/div>\n<ol>\n<li>Used in the manufacture of PVC plastics.\n<\/li>\n<li>Used in miner&#8217;s lamp as fuel.\n<\/li>\n<li>\n<div>Used in making synthetic fiber.\n<\/div>\n<p>\u00a0<\/li>\n<\/ol>\n<\/li>\n<\/ol>\n<p><strong>TEST FOR UNSATURATION<br \/>\n<\/strong>Unsaturated compound decolorizes bromine water.<\/p>\n<p>\u00a0<strong>Evaluation<\/strong><\/p>\n<ol>\n<li>Give a chemical test to distinguish between ethyne and ethene.\n<\/li>\n<li>Write two balanced equations to show addition reaction of ethyne.\n<\/li>\n<\/ol>\n<p>\u00a0<strong>AROMATIC HYDROCARBONS<br \/>\n<\/strong>These are hydrocarbons that have the same structure as benzene.<br \/>\nBenzene is a typical aromatic compound with molecular formula of C<sub>6<\/sub>H<sub>6<\/sub>. <\/p>\n<p>\u00a0<strong>STRUCTURE OF BENZENE<br \/>\n<\/strong>Over the years, there has been a controversy on the structure of benzene. But in 1865, August Kekule suggested a structure for benzene. Kekule proposed that benzene has a ring structure with alternate single and double carbon-carbon bonds as shown below:<\/p>\n<p>\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<br \/>\n\u00a0which can be conveniently represented as<\/p>\n<p>\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<br \/>\n\u00a0These two forms of benzene structure are known as resonance forms. Resonance occurs when two forms of the same compound have the same arrangement of atoms but differ in the arrangement of electrons that form the bonds.<\/p>\n<p>\u00a0The Kekule structure of benzene accounted for the stability of the six carbon atoms but it was unable to explain why a highly unsaturated compound failed to undergo many of the addition reactions like decolourising bromine water, reaction with hydrogen halides etc; characteristic of alkenes.<\/p>\n<p>\u00a0Benzene undergoes mostly substitution reactions. Thus, the structural formula with threedouble bonds describing the benzene molecule does not agree with the chemical behaviour of benzene. Therefore, the bonding in benzene cannot be described as three double bonds and three single bonds as proposed by Kekule but rather the bonding must be considered as a delocalized electron cloud spread out over the whole benzene ring. Hence, the modern structure of benzene is considered to be a plain hexagon with an inscribed ring which represents the electron cloud spread out over the whole benzene ring as shown below:<\/p>\n<p>\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<strong>PREPARATION: <\/strong>Benzene can be prepared from:<strong><br \/>\n\t\t<\/strong>1.  \u00a0\u00a0\u00a0\u00a0Coal tar: The destructive distillation of coal produced coal tar which contains benzene.<br \/>\n2.  \u00a0\u00a0\u00a0\u00a0Petroleum: The dehydrogenated of alkane using vanadium (V) oxide (V<sub>2<\/sub>O<sub>5<\/sub>) as catalyst at 500<sup>o<\/sup>C and 20 atm gives benzene.<br \/>\n\u00a0\u00a0\u00a0\u00a0C<sub>6<\/sub>H<sub>14 <\/sub>    V<sub>2<\/sub>O<sub>2<\/sub>C<sub>6<\/sub>H<sub>6<\/sub>  +  4H<sub>2<\/sub><br \/>\n\t<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th43.png\" alt=\"\"\/>The process is known as catalytic reforming.<br \/>\n3. \u00a0\u00a0\u00a0\u00a0 Polymerization of ethyne<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0801_Week8SS2Th44.png\" alt=\"\"\/>\u00a0\u00a0\u00a0\u00a03 ( H \u2013 C = C \u2013 H )           C<sub>6<\/sub>H<sub>6<\/sub><\/p>\n<p>\u00a0<strong>Evaluation<\/strong><\/p>\n<ol>\n<li>Describe three methods of preparing benzene.\n<\/li>\n<\/ol>\n<ol>\n<li>Draw the resonance structures of benzene structure of benzene.\n<\/li>\n<\/ol>\n<p>\u00a0<strong>PHYSICAL PROPERTIES <\/strong><br \/>\n\t1.\u00a0\u00a0\u00a0\u00a0It has a pleasant smell.<br \/>\n2.\u00a0\u00a0\u00a0\u00a0It has boiling point of 80<sup>o<\/sup>C.<br \/>\n3.\u00a0\u00a0\u00a0\u00a0It is insoluble in water.<br \/>\n4.\u00a0\u00a0\u00a0\u00a0It burns with sooty flame.<\/p>\n<p>\u00a0<strong>CHEMICAL PROPERTIES<br \/>\n<\/strong>Benzene can undergo both addition reaction and substitution reaction.<\/p>\n<ol>\n<li>\n<div>Addition Reaction:\n<\/div>\n<p> i.   Hydrogenation:  Benzene reduces to cyclo-hexane if hydrogen gas is passed through finely divided nickel at 150<sup>o<\/sup>C.\n<\/li>\n<\/ol>\n<p>\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0ii.   Halogenation:  In the presence of ultra-violet light, benzene reacts with halogen to produce cyclic compound.<br \/>\n\u00a0\u00a0\u00a0\u00a0<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/p>\n<p>\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<br \/>\n\u00a02.  \u00a0\u00a0\u00a0\u00a0Substitution Reaction: Benzene undergoes substitution reaction due to presence of single bonds in its structure.<br \/>\ni.  \u00a0\u00a0\u00a0\u00a0Halogenation:<\/p>\n<p>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/p>\n<p>\u00a0<br \/>\n\u00a0<br \/>\n\u00a0ii. \u00a0\u00a0\u00a0\u00a0 Nitration:  This occurs in the mixture of HNO<sub>3<\/sub> and H<sub>2<\/sub>SO<sub>4<\/sub> together with benzene<\/p>\n<p>\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/p>\n<p>\u00a0iii.  Sulphonation: Benzene react with concentrated H<sub>2<\/sub>SO<sub>4<\/sub> to form benzene sulphonic acid.<\/p>\n<p>\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<br \/>\n\u00a0iv.  Alkylation:-  It involves reactions of benzene with halo-alkanes in the presence of AlCl<sub>3<\/sub>.<\/p>\n<p>\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<br \/>\n\u00a0<strong>USES<\/strong><br \/>\n\t1.   \u00a0\u00a0\u00a0\u00a0It is used as a solvent to dissolve organic.<br \/>\n2.\u00a0\u00a0\u00a0\u00a0It is used as fuel in petrol.<br \/>\n3. \u00a0\u00a0\u00a0\u00a0It is used in the manufacture of aromatic compound e.g. benzoic acid.<\/p>\n<p>\u00a0<strong>GENERAL Evaluation\/REVISION<br \/>\n<\/strong><\/p>\n<ol>\n<li>\n<div>How would you obtain ethanal from ethyne? Give the equation for the reaction.\n<\/div>\n<ol>\n<li>Describe how to prepare ethyne in the laboratory.\n<\/li>\n<li>What is resonance? Give the resonance structure of benzene.\n<\/li>\n<\/ol>\n<\/li>\n<li>Explain why hydrogen fluoride exists as a liquid whereas hydrogen chloride is a gas at room temperature.\n<\/li>\n<li>\n<div> Explain why HCl in water conducts electricity but HCl in methyl benzene does not conduct electricity.\n<\/div>\n<p>\u00a0<\/li>\n<\/ol>\n<p><strong>READING ASSIGNMENT<br \/>\n<\/strong>New School Chemistry for Senior Secondary School by .O.Y. Ababio (6<sup>th<\/sup> edition), pages 535-539.<\/p>\n<p>\u00a0<strong>WEEKEND ASSIGNMENT<br \/>\n<\/strong><strong>SECTION A:<\/strong> Write the correct option ONLY<br \/>\n1.\u00a0\u00a0\u00a0\u00a0Which of the following hydrocarbons is alkyne?<br \/>\n        a. C<sub>2<\/sub>H<sub>4<\/sub>\u00a0\u00a0\u00a0\u00a0b. C<sub>2<\/sub>H<sub>6<\/sub> c. C<sub>2<\/sub>H<sub>2<\/sub> d. C<sub>3<\/sub>H<sub>8<\/sub><br \/>\n\t2.\u00a0\u00a0\u00a0\u00a0The final product of complete reaction between ethyne and hydrogen gas is<br \/>\na. ethane   b. methyl ethane c. ethane\u00a0\u00a0\u00a0\u00a0d. hydroethyne<br \/>\n3.\u00a0\u00a0\u00a0\u00a0Ethynepolymerizes in the presence of organo nickel complex as catalyst to form a. polythene b. benzene c. polythene d. methyl benzene<br \/>\n4.\u00a0\u00a0\u00a0\u00a0Which of these compounds exhibits resonance? a. Ethanol b. Ethane<br \/>\n\u00a0\u00a0\u00a0\u00a0c. Benzene d. Butyne<br \/>\n5.\u00a0\u00a0\u00a0\u00a0Which of these is an aromatic hydrocarbon? a. Benzene b. Cyclohexane<br \/>\n\u00a0\u00a0\u00a0\u00a0c. Ethene d. Methylamine<\/p>\n<p>\u00a0<strong>SECTION B<br \/>\n<\/strong>1\u00a0\u00a0\u00a0\u00a0a.With the aid of a labeled diagram, describe the laboratory preparation of ethyne.<br \/>\n\u00a0\u00a0\u00a0\u00a0b. Give a chemical test to distinguish between ethane and ethyne.<br \/>\n2\u00a0\u00a0\u00a0\u00a0a.What is resonance? Draw two resonance structure of benzene.<br \/>\n\u00a0\u00a0\u00a0\u00a0b. Write balanced equation to the following reactions of benzene:<\/p>\n<ol>\n<li>Reaction with ethene(ii) Reaction with chlorine.\n<\/li>\n<\/ol>\n<p>\u00a0<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u00a0WEEK EIGHT TOPIC:ALKYNES CONTENT Nomenclature Preparation, Properties and Uses Aromatic Hydrocarbons: Benzene Structure Preparation, Properties&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1,268],"tags":[],"class_list":["post-3366","post","type-post","status-publish","format-standard","hentry","category-posts","category-third-term-ss2-chemistry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/posts\/3366","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/comments?post=3366"}],"version-history":[{"count":1,"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/posts\/3366\/revisions"}],"predecessor-version":[{"id":3367,"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/posts\/3366\/revisions\/3367"}],"wp:attachment":[{"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/media?parent=3366"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/categories?post=3366"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/tags?post=3366"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}