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Give the preparations of alkane ? Give the general reaction. |
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Answer» Solution :For, the preparation of ALKANE, important reactions are as follows : (i) From unsaturated hydrocarbons :  `underset("Alkyne")(-C-=C)+2H_(2) underset("Pressure")overset(Ni, Delta)rarr-underset("Alkane")(underset(H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)overset(H)overset(|)(C)-)` ......(ii) (ii)From alkyl halides : `underset("Alkyl halide")(R-CL)+H_(2)underset("Reduction")overset(Zn+HCl(dil))rarr underset("Alkane")(RH)+HCl` (III) Wurtz reaction of from alkyl halide using wattz reaction : `2Na+R-underset("Alkyl halide")(Cl+Cl-R) overset(+NaOH(CaO))rarr underset("Alkane")(R-R)+2NaCl` * SODA lime means mix of CaO and NaOH. (iv) From carboxylic acid : `underset("Carbocylic acid")(RCOOH)underset(Delta)overset("Soda lime")rarr (RCOO^(-)Na^(+)) underset((CaO))overset(+NaOH)rarr underset("Alkane")(RH+Na_(2)CO_(3))` * Soda lime means mix of CaO and NaOH. (v) Kolbe.s electrolysis or preparation of alkene from the salt of carboxylc acid in the form of sodium of pottassium into the presence of aqueous solution during electrolysis. `underset("Carbocylic acid")(RCOOH)underset(-H_(2)O)overset(+NaOH)rarr underset("Sodium carbocylate")((RCOO^(-)Na^(+)))underset(-2CO_(2), -H_(2))overset("Electrolysis")rarrunderset("Alkane")(R-R)` Petroleum and Natural gas are the main sources. [Note : Replace R with `-CH_(3), CH_(3) CH_(2)-` in reaction try it] |
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