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A chloro compound (A) showed the following properties, i. decolourised bromine in CCl_4 (ii). Absorbed hydrogen catalytically. (iii). Gave a red precipitate with ammoniacal cuprous chloride ltbr. (iv). When vaporised 1.49 gm of (A) gave 448 ml of vapours at STP. Identify (A) and write doen the equiation for the reaction is step 3.

Answer» <html><body><p></p>Solution :Step 1: To determine the molecular mass of compound (A): <br/> 448 <a href="https://interviewquestions.tuteehub.com/tag/ml-548251" style="font-weight:bold;" target="_blank" title="Click to know more about ML">ML</a> of vapours at STP weigh 1.49 gm <br/> 22400 ml of vapour at STP will weigh <br/> `=(1.49xx22400)/(448)=74.5gm` <br/> Thus, the molecular mass of compound (A) is 74.5 a.m.u. <br/> step 2. To identify the functional groups: <br/> (i). Since (A) decolourises `(Br_2)/(C Cl_4)`, is (A) must be an <a href="https://interviewquestions.tuteehub.com/tag/unsaturated-721485" style="font-weight:bold;" target="_blank" title="Click to know more about UNSATURATED">UNSATURATED</a> compound. This is further supported by the <a href="https://interviewquestions.tuteehub.com/tag/fact-982736" style="font-weight:bold;" target="_blank" title="Click to know more about FACT">FACT</a> that (A) also absorbs hydrogen catalytically. <br/> (ii) Since (A) gave a <a href="https://interviewquestions.tuteehub.com/tag/precipitate-1162804" style="font-weight:bold;" target="_blank" title="Click to know more about PRECIPITATE">PRECIPITATE</a> with ammoniacal `CuLl`, it must be a terminal acetyline, ie.e, it must contain the group `(---C--<a href="https://interviewquestions.tuteehub.com/tag/ch-913588" style="font-weight:bold;" target="_blank" title="Click to know more about CH">CH</a>)` <br/> Step 3. To determine the molecular formula of the compound (A): <br/> Molecular mass of `(---C---CH)` group `=12+12+1=25amu` <br/> Atomic mass of chlorine`=35.5a.m.u` <br/> Molecular mass of the compound `=74.5 amu` <br/> molecular mass of the remaining portion of compound `(A)=74.5-25-35.5=14` <br/> Since the molecualr mass of a `(CH_2)` group is 14 compound (A) contains a chlorine atom, one `(CH_2)` group, and one terminal acetylene group i.e., `(---C--CH)`, therefore the structure of the organic compound is <br/> `underset(3-"chloroprop-1-yne") (ClCH_2)--C-=CH+CuCl+NH_4OHrarrunderset("Copper-3-chlorprop-1-1ynide")(ClCH_2)-=C Cu+NH_4Cl+H_2O`</body></html>


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