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A gaseous hydrocarbon on analysis gave the following data : (i) It contains C = 82.7% and H = 17.3% (ii) The mass of 132 mL (measured at S.T.R) of it is 0.342 g.Find the molecular formula of the hydrocarbon.

Answer» <html><body><p></p><a href="https://interviewquestions.tuteehub.com/tag/solution-25781" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTION">SOLUTION</a> :Calculation of empirical formula : <br/> <img src="https://doubtnut-static.s.llnwi.net/static/physics_images/NTN_HCS_ISC_CHE_XI_P1_C01_SLV_078_S01.png" width="80%"/> <br/> `therefore` The empirical formula of the given hydrocarbon is `C_(<a href="https://interviewquestions.tuteehub.com/tag/2-283658" style="font-weight:bold;" target="_blank" title="Click to know more about 2">2</a>)H_(5)`. <br/> Calculation of molecular formula : <br/> Empirical formula mass = `(2 xx 12.01) + (5 xx 1.008) = 29.06` amu. As discussed earlier, the <a href="https://interviewquestions.tuteehub.com/tag/volume-728707" style="font-weight:bold;" target="_blank" title="Click to know more about VOLUME">VOLUME</a> occupied by one <a href="https://interviewquestions.tuteehub.com/tag/gram-1010695" style="font-weight:bold;" target="_blank" title="Click to know more about GRAM">GRAM</a> molecular mass of a substance at S.T.R is 22.4 L (22400 mL) <br/> `therefore` The gram molecular mass of the given hydrocarbon `=0.342/132 xx 22400 = 58.0`<br/> <a href="https://interviewquestions.tuteehub.com/tag/hence-484344" style="font-weight:bold;" target="_blank" title="Click to know more about HENCE">HENCE</a>, its molecular mass = 58.0 amu `n = ("Molecular mass")/("Empirical formula mass") = 58.0/29.06 =2` <br/> `therefore` Molecular mass = 2 `xx` Empirical formula <br/> `=2 xx C_(2)H_(5) = C_(4)H_(10)` <br/> Hence, the molecular formula of the given hydrocarbon is `C_(4)H_(10)`.</body></html>


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