Question

(a) An organic compound (A) of molecular formula $C_2{H}_{4}O$ is prepared by the reduction of compound (B) of molecular formula $C_2{H}_{3}N$ dissolved in ether, with $Sn{Cl}_2$ and $HCl$. Compound (A) reduces Tollen's reagent. When a drop of conc. $H_2{SO}_4$ is added to compound (A), it polymerises to give a cyclic compound (C). Identify (A), (B) and (C). Explain the reactions?

(b) Ionic conductance at infinite dilution of ${Al}^{3+}$ and ${SO}_4^{2-}$ are $189{ohm}^{-1}$ ${cm}^2$ $gm.{equiv}^{-1}$ and $160{ohm}^{-1}$ ${cm}^2$ $gm.{equiv}^{-1}$. Calculate equivalent and molar conductance of the electrolytes at infinite dilution?

Answer 1

${\Lambda }_{eq}^0\left(A{l}_2\right(S{O}_4{)}_3)=2{\lambda }_{eq}^0(A{l}^{3+})+3{\lambda }_{eq}^0(S{O}_4^{2-})$
${\Lambda }_{eq}^0\left(A{l}_2\right(S{O}_4{)}_3)=2(189{ohm}^{-1}{cm}^{2}gm.{equiv}^{-1})+3(160{ohm}^{-1}{cm}^{2}gm.{equiv}^{-1})$
${\Lambda }_{eq}^0\left(A{l}_2\right(S{O}_4{)}_3)=858{ohm}^{-1}{cm}^{2}gm.{equiv}^{-1}$
${\Lambda }_M^0\left(A{l}_2\right(S{O}_4{)}_3)={\Lambda }_{eq}^0(A{l}_2\left(S{O}_4{)}_3\right)\times \frac{\text{Molecular weight}}{\text{Equivalent weight}}$
${\Lambda }_M^0\left(A{l}_2\right(S{O}_4{)}_3)=858{ohm}^{-1}{cm}^{2}gm.{equiv}^{-1}\times \frac{\text{342.1}}{\text{57}}$
${\Lambda }_M^0\left(A{l}_2\right(S{O}_4{)}_3)=5149.5{ohm}^{-1}{cm}^{2}gm.{equiv}^{-1}$