Tejas posted an Question
August 05, 2020 • 02:15 am 30 points
  • IIT JAM
  • Chemistry (CY)

The number of vibrational mode(s) of acetylene (chch) molecule that can be detected using infrared spectroscopy is

The number of vibrational mode(s) of a carbon dioxide molecule that can be detected using infrared spectroscopy is

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    Dinesh khalmaniya 1 best-answer

    check IR modes of acetylene in 3d https://www.chem.purdue.edu/jmol/vibs/c2h2.html

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    check this. it have 7 According to 3n-5

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    check this

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    Priyanshu kumar Best Answer

    3N-5 for linear ...so we get 7 normal modes of vibration

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    In this which are IR active.... this is my question....

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    3 are IR active 4 inactive...check vibration in molecules of C2H2 https://www.chem.purdue.edu/jmol/vibs/c2h2.html

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    IR active means dipole moment changes during vibration...If symmetrical bond then IR inactive as dipole moment doesnt changes during vibration

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    Tejas check the link above...👆

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    sir... here two asymmetric vibration ....hence it will show Two IR active mode... But in your reference Document...only one asymmetric stretching shown...

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    ]Is only one possible at one time??

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    tejas i have send u 3d reference...The 7 modes you have ...have you count the total IR active in it??

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    yes 3 are IR active according to ur reference

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    yes as these are made like doubly degenerate etc...so better u get from 3d reference

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    ok sir.. 👍

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    3 active and 4 inactive 👍

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