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Carbon and its Compounds — Science STD 10 — Question

CBSE BoardEnglish MediumSTD 10ScienceCarbon and its Compounds5 Marks
Question
Give the structural differences between saturated and unsaturated hydrocarbons with two examples, each.
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Answer

Saturated hydrocarbons or alkanes contain either C—C or C—H bonds in their molecules. These are represented by the general formula CnH2n + 2 For example,

$\ \ \ \ \ \ \ \ \text{H}\ \ \ \ \ \text{H}\\\ \ \ \ \ \ \ \ \ |\ \ \ \ \ \ \ |\\\text{H}-\text{C}-\text{C}-\text{H}\\\ \ \ \ \ \ \ \ \ |\ \ \ \ \ \ \ |\\\ \ \ \ \ \ \ \ \text{H}\ \ \ \ \ \text{H}\\\ \ \ \ \ \ \ \ \text{Ethane}$  $\ \ \ \ \ \ \ \text{H}\ \ \ \ \ \text{H}\ \ \ \ \ \text{H}\\\ \ \ \ \ \ \ \ |\ \ \ \ \ \ \ |\ \ \ \ \ \ \ |\\\text{H}-\text{C}-\text{C}-\text{C}-\text{H}\\\ \ \ \ \ \ \ \ \ |\ \ \ \ \ \ |\ \ \ \ \ \ \ |\\\ \ \ \ \ \ \ \ \text{H}\ \ \ \ \text{H}\ \ \ \ \ \ \text{H}\\\ \ \ \ \ \ \ \ \ \ \text{Propane}$

Unsaturated hydrocarbons contain either atleast one >C = C< bond or triple —C ≡ C— bond in their molecules. These may be either alkenes or alkynes in nature. The general formula of alkenes is CnH2n while that of alkynes is CnH2n - 2 for example,

$\ \ \ \ \ \ \ \ \text{H}\ \ \ \ \ \text{H}\\\ \ \ \ \ \ \ \ \ |\ \ \ \ \ \ \ |\\\text{H}-\text{C}=\text{C}-\text{H}\\\ \ \ \ \text{Ethene}$  $\ \ \ \ \ \ \ \ \text{H}\\\ \ \ \ \ \ \ \ \ |\\\text{H}-\text{C}-\text{C}=\text{C}-\text{H}\\\ \ \ \ \ \ \ \ \ |\ \ \ \ \ \ \ |\ \ \ \ \ \ \ |\\\ \ \ \ \ \ \ \ \text{H}\ \ \ \ \ \text{H}\ \ \ \ \ \ \text{H}\\\ \ \ \ \ \ \ \ \text{Propene}$  $\text{H}-\text{C}\equiv\text{C}-\text{H}\\\ \ \ \ \ \ \text{Ethyne}$  $\ \ \ \ \ \ \ \ \text{H}\\\ \ \ \ \ \ \ \ \ |\\\text{H}-\text{C}-\text{C}\equiv\text{C}-\text{H}\\\ \ \ \ \ \ \ \ \ |\\\ \ \ \ \ \ \ \ \text{H}\\\ \ \ \ \text{Propyne}$

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