Introduction to Organic Chemistry

Organic chemistry is a branch of chemistry which deals with compounds of carbon. In the early 19th century, a Swedish chemist Jacob Berzelius proposed the ‘Vital Force Theory’. According to this theory the organic compounds can only be isolated from the living beings and cannot be synthesised in the laboratory. In 1828, Friedrich Wohler, a German chemist, accidentally synthesised urea in his laboratory, from the ammonium cyanate. This synthesis clearly showed that no vital force was involved in the production of the organic compounds. Organic compounds are the compounds of carbon except oxides of carbon and carbonates and bicarbonates. Inorganic compounds are the compounds of elements other than carbon. Oxides of carbon, carbonates and bicarbonate are also classified as inorganic compounds. In our daily life we come across several organic compounds such as clothes, soaps, detergents, plastic articles, cosmetics, fuels, food etc. There are various ways to represent the structures of organic compounds which include complete structural formula, condensed structural formula and bond-line structural formula. Molecular models are the physical means to have better visualisation and perception of three dimensional shapes of molecules. Hydrocarbons are the organic compounds made up of hydrogen and carbon only. Hydrocarbons can be broadly classified in two categories, saturated and unsaturated compounds. Open chain saturated hydrocarbons are called alkanes. Open chain unsaturated compounds can be of two types; alkenes or alkynes. We apply certain set of rules to identify a hydrocarbon from its molecular formula.

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  • Q1

    Identify the first organic compound synthesised in the laboratory.

    Marks:1
    Answer:

    Urea.

    Explanation:

    The first organic compound synthesised in the laboratory was urea. It was synthesised by a chemist named Friedrich Wohler from an inorganic compound i.e. ammonium cyanate.

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  • Q2

    Pick the correct statement from the following.

    Marks:1
    Answer:

    All organic compounds contain carbon element.

    Explanation:

    Carbon is an essential element of every organic compound. These compounds show isomerism and only dissolve in non–polar solvents like benzene. They do not dissolve in polar solvents like water. However, all carbon containing compounds are not organic. For example: carbon dioxide is not organic compound.

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  • Q3

    Marks:1
    Answer:

    alkane.

    Explanation:

    The compound contains all single bonds and thus it is a saturated hydrocarbon. It is also known as alkanes or paraffins.

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  • Q4

    Food, clothes, medicines, cosmetics etc. are made of organic compounds. Identify the properties which are responsible for the existence of large number of organic compounds.

    Marks:1
    Answer:

    tetravalency and catenation.

    Explanation:

    Carbon can form four covalent bonds. This property of carbon is known as tetravalency.

    It also possesses a unique property of self–linking with itself. This property of carbon is known as catenation.

    These two unique properties of carbon give rise to a large number of compounds.

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  • Q5

    Identify the carbon compound which is not an organic compound.

    Marks:1
    Answer:

    NH4CNO

    Explanation:

     NH4CNO is ammonium cyanate. It is an inorganic compound.

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