Question

Silanes are silicon hydrides of general formula $S{i}_n{H}_{2n+2}$ and have several applications. From thedata given below, the bond dissociation enthalpy of Si-Si bond (in $kJmo{l}^{-1}$ ) is

Given:

∆H of the reaction $2Si\left(s\right)+3H_2\left(g\right)\to S{i}_2{H}_6\left(g\right)$ is 80.3 $kJmo{l}^{-1}$

Bond dissociation enthalpy for H - H = 436 $kJmo{l}^{-1}$

Bond dissociation enthalpy for Si - H = 304 $kJmo{l}^{-1}$

${\Delta }_{\mathrm{f}}\mathrm{H}[\mathrm{Si}(\mathrm{g})]=450{\mathrm{kJmol}}^{-1}$

Answer 1

Answer: 304

$8.03=2\times 405+3\times 436-\left[\left(Si-Si\right)+6\left(304\right)\right]$

(Si - Si) Bond energy $=304kJmo{l}^{-1}$