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    Question-Alkenes react with hydrogen gas in the presence of a nickel catalyst. 0.2 mol of an alkene reacted completely with 19.2 dm3 of hydrogen gas at room temperature and pressure. How many carbon carbon double bonds are there in a molecule of this alkene? [The molar volume of a gas is 24.0 dm3 mol–1 at room temperature and pressure]. How do I solve this???
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    Find the number of moles of hydrogen gas.

    1 mole of double bonds will require 1 mole of hydrogen gas.

    So the ratio of the number of moles of the alkene to the number of moles of hydrogen gas gives you the answer.
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    (Original post by BobbJo)
    Find the number of moles of hydrogen gas.

    1 mole of double bonds will require 1 mole of hydrogen gas.

    So the ratio of the number of moles of the alkene to the number of moles of hydrogen gas gives you the answer.
    Why is the ratio of double bonds to hydrogen 1:1 ???
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    (Original post by Vidya Das)
    Why is the ratio of double bonds to hydrogen 1:1 ???
    You need one H2 molecule to saturate one C=C.

    Try it with ethene, propadiene, buta-1,2,3-triene. You'll realise that the above holds true
 
 
 
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