Question

$I{E}_1$ and $I{E}_2$ of Mg are 178 and 348 Kcal ${mol}^{-1}$ respectively. The energy required for the reaction

$M_{\left(g\right)}$ $\to$ ${Mg}^{2+}$_(g) + 2$e^{-}$ is

• A. +170 KCal
• B. +526 KCal
• C. -170 KCal
• D. -52 KCal

Answer 1

The correct option is B

+526 KCal

$M_{\left(g\right)}$ ------------ $M_{\left(g\right)}^{+}$ + $e^{-}$ $I{E}_1$ = +178 Kcal

$M_{\left(g\right)}^{+}$ $⟶$ $M_{\left(g\right)}^{+2}$ + $e^{-}$ $I{E}_2$ =+ 348 Kcal

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$M_{\left(g\right)}$ $⟶$ $M_{\left(g\right)}^{+2}$ + 2 $e^{-}$ I.E = $I{E}_1$+ $I{E}_2$ = 178 + 348

= 526 KCal