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In a compound, C, H and N are present in the ratio `9 : 1: 3.5` by weight. If the molecular weight. If the molecular weight of the compound is 108, what is the number of hydrogen atoms present in the molecular formula of the compound ? |
Answer» Correct Answer - `=8` Step I. Empirical formula of the compound `{:("Element","Percentage/weight (ratio)","Gram atoms (Moles)","Atomic ratio (Molar ratio)","Simplest whole no. ratio"),("C",9,(9)/(12)=0.75,(0.75)/(0.25)=3,3),("H",1,(1)/(1)=1.0,(1.00)/(0.25)=4,4),("N",3.5,(3.5)/(14)=0.25,(0.25)/(0.25)=1,1):}` Empirical formula of the compound `= C_(3)H_(4)N` Step II. Molecular formula of the compound Empirical formula mass `= 3 xx 12 + 4 xx 1 +14 = 54 u` Molecular mass = 108 u (given) `n=("Molecular mass")/("Empirical formula mass")=((108u))/((54u))=2` Molecular formula of the compound `= n xx` Empirical formula `:.` Number of hydrogen atoms present = 8. |
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