Chapter 16

Calculate the enthalpy change for the reaction, $$ \mathrm{XeF}_{4} \longrightarrow \mathrm{Xe}^{+}+\mathrm{F}^{-}+\mathrm{F}_{2}+\mathrm{F} $$ The average \(\mathrm{Xe}-\mathrm{F}\) bond energy is \(34 \mathrm{kcal} / \mathrm{mol}\), first I.E. of \(\mathrm{Xe}\) is 279 kcal/mol, electron affinity of \(\mathrm{F}\) is 85 kcal/ mol and bond dissociation energy of \(\mathrm{F}_{2}\) is \(38 \mathrm{kcal} / \mathrm{mol}\).

\(1 \mathrm{~g}\) of \(\mathrm{Mg}\) atoms in the vapour phase absorbs \(50.0 \mathrm{~kJ}\) of energy. Find the composition of \(\mathrm{Mg}^{+}\) and \(\mathrm{Mg}^{2+}\) formed as a result of absorption of energy. \(\mathrm{IE}_{1}\) and \(\mathrm{IE}_{2}\) for \(\mathrm{Mg}\) are 740 and \(1450 \mathrm{~kJ} \mathrm{~mol}^{-1}\) respectively.

A mixture contains atoms of fluorine and chlorine. The removal of an electron from each atom of sample absorbs \(284 \mathrm{~kJ}\) while the addition of an electron to each atom of mixture releases \(68.8 \mathrm{~kJ}\). Determine the percentage composition of mixture. Given \(\mathrm{IE}_{1}\) for \(\mathrm{F}\) and \(\mathrm{Cl}\) are \(27.91 \times 10^{-22}\) and \(20.77 \times 10^{-22} \mathrm{~kJ} /\) atom respectively and \(\mathrm{EA}_{1}\) for \(\mathrm{F}\) and \(\mathrm{Cl}\) are \(-5.53 \times 10^{-22}\) and \(-5.78 \times 10^{-22} \mathrm{~kJ} /\) atom respectively.

Calculate the \(\%\) ionic character in \(\mathrm{HCl}\) molecule. Given bond length of \(\mathrm{HCl}\) is \(1.275 \AA\) and \(\mu_{\mathrm{HCi}}=1.03\) debye.

The dipole moment of \(\mathrm{LiH}\) is \(1.964 \times 10^{-27} \mathrm{Cm}\) and the intermolecular distance between \(\mathrm{Li}\) and \(\mathrm{H}\) in this molecule is \(1.596 \AA\). What is per cent ionic character in molecule?

Assuming covalent radii to be additive property; calculate the iodine-iodine distances in \(o-, m-, p\) -di-iodobenzene. The benzene ring is regular hexagon and each \(C-\) I bond lies on a line passing through the centre of hexagon. The \(\mathrm{C}-\mathrm{C}\) bond length in \(\mathrm{C}_{6} \mathrm{H}_{6}\) are \(1.40 \AA\) and covalent radius of iodine and carbon atom are \(1.33 \AA\) and \(0.77 \AA\). Also neglect different overlapping effect.

Metal carbonyls having formula \(M(\mathrm{CO})_{x}\), where \(x\) is the number of carbonyl units co-ordinated to metal \(M\) are formed by Fe, \(\mathrm{Cr}\) and Ni. If effective atomic number of each metal is 36, what are the formula of metal carbonyls?

\(100 \mathrm{~mL}\) of \(1 \times 10^{-2} M\) aqueous solution of an organic compound were shaken with \(50 \mathrm{~mL}\) of an organic solvent till equilibrium is attained. Calculate the concentration of organic compound in organic solvent. Given that distribution coefficient of organic compound for the given solvent is 50 in favour of organic solvent.

Distribution coefficient of an organic acid between water and benzene is \(4.1\) is favour of \(\mathrm{C}_{6} \mathrm{H}_{6}\). If \(5 \mathrm{~g}\) of the acid is distributed in between 50 \(\mathrm{mL}\) of benzene and \(100 \mathrm{~mL}\) of water, calculate the concentration of the acid in two solvents.