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JEE Main & Advanced Chemistry Some Basic Concepts of Chemistry / रसायन की कुछ मूलभूत अवधारणाएँ Question Bank Self Evaluation Test - Some Basic Concepts of Chemistry

  • question_answer
    A gaseous compound of nitrogen and hydrogen contains 12.5% (by mass) of hydrogen. The density of the compound relative to hydrogen is 16. The molecular formula of the compound is:

    A) \[N{{H}_{2}}\]

    B) \[{{N}_{3}}H\]

    C) \[N{{H}_{3}}\]            

    D) \[{{N}_{2}}{{H}_{4}}\]

    Correct Answer: D

    Solution :

    [d] In an unknown compounds containing N and H given % of H =12.5%
    % of \[N=100-12.5=87.5%\]
    Element Percentage Atomic ratio Simple ratio
    Elements Percentage Atomic ratio Simple ratio
    H 12.5% \[\frac{12.5}{1}=12.5\] \[\frac{12.5}{6.25}=2\]
    N 87.5 \[\frac{87.5}{14}=6.25\] \[\frac{6.25}{6.25}=1\]
    2 \[\times \] vapour density = Mol. wt = mol wt. \[=16\times 2=32.\]
    Molecular formula = n \[\times \] empirical formula mass \[n=\frac{32}{16}=2\]
    \[\therefore \] Molecular formula of the compound will be \[={{\left( N{{H}_{2}} \right)}_{2}}={{N}_{2}}{{H}_{4}}\]
     


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