Chapter 22

What is the anhydride for each of the following acids: (a) ${\mathrm{H}}_2{\mathrm{SO}}_4$, (b) ${\mathrm{HClO}}_3$ (c) ${\mathrm{HNO}}_2$, (d) ${\mathrm{H}}_2{\mathrm{CO}}_3$ (e) ${\mathrm{H}}_3{\mathrm{PO}}_4?$

Explain why ${\mathrm{SO}}_2$ can be used as a reducing agent but ${\mathrm{SO}}_3$ cannot.

A sulfuric acid plant produces a considerable amount of heat. This heat is used to generate electricity, which helps reduce operating costs. The synthesis of ${\mathrm{H}}_2{\mathrm{SO}}_4$ consists of three main chemical processes: (1) oxidation of $\mathrm{S}$ to ${\mathrm{SO}}_2$, (2) oxidation of ${\mathrm{SO}}_2$ to ${\mathrm{SO}}_3$, (3) the dissolving of ${\mathrm{SO}}_3$ in ${\mathrm{H}}_2{\mathrm{SO}}_4$ and its reaction with water to form ${\mathrm{H}}_2{\mathrm{SO}}_4$. If the third process produces $130\mathrm{kJ}/\mathrm{mol}$, how much heat is produced in preparing a mole of ${\mathrm{H}}_2{\mathrm{SO}}_4$ from a mole of $\mathrm{S}$ ? How much heat is produced in preparing a ton of ${\mathrm{H}}_2{\mathrm{SO}}_4$ ?

(a) What is the oxidation state of $\mathrm{P}$ in ${\mathrm{PO}}_4{}^{3-}$ and of $\mathrm{N}$ in ${\mathrm{NO}}_3^{-}?(\mathbf{b})$ Why doesn't $\mathrm{N}$ form a stable ${\mathrm{NO}}_4^{3-}$ ion analogous to $\mathrm{P}$ ?

Silicon has a limited capacity to form linear, $\mathrm{Si}-\mathrm{Si}$ bonded structures similar to those formed by carbon. (a) Predict the molecular formula of a hydride of silicon that contains a chain of three silicon atoms. (b) Write a balanced equation for the reaction between oxygen and the compound you predicted in part (a).

Ultrapure germanium, like silicon, is used in semiconductors. Germanium of "ordinary" purity is prepared by the high-temperature reduction of ${\mathrm{GeO}}_2$ with carbon. The Ge is converted to ${\mathrm{GeCl}}_4$ by treatment with ${\mathrm{Cl}}_2$ and then purified by distillation; ${\mathrm{GeCl}}_4$ is then hydrolyzed in water to ${\mathrm{GeO}}_2$ and reduced to the elemental form with ${\mathrm{H}}_2$. The element is then zone refined. Write a balanced chemical equation for each of the chemical transformations in the course of forming ultrapure Ge from ${\mathrm{GeO}}_2$.

Complete and balance the following equations: (a) ${\mathrm{MnO}}_4^{-}(aq)+{\mathrm{H}}_2{\mathrm{O}}_2(aq)+{\mathrm{H}}^{+}(aq)⟶$ (b) ${\mathrm{Fe}}^{2+}(aq)+{\mathrm{H}}_2{\mathrm{O}}_2(aq)⟶$ (c) ${\mathrm{I}}^{-}(aq)+{\mathrm{H}}_2{\mathrm{O}}_2(aq)+{\mathrm{H}}^{+}(aq)⟶$ (d) $\mathrm{Cu}(\mathrm{s})+{\mathrm{H}}_2{\mathrm{O}}_2(aq)+{\mathrm{H}}^{+}(aq)⟶$ (e) ${\mathrm{I}}^{-}(aq)+{\mathrm{O}}_3(\mathrm{g})⟶{\mathrm{I}}_2(\mathrm{s})+{\mathrm{O}}_2(\mathrm{g})+{\mathrm{OH}}^{-}(aq)$

Hydrogen peroxide is capable of oxidizing (a) hydrazine to ${\mathrm{N}}_2$ and ${\mathrm{H}}_2\mathrm{O}$, (b) ${\mathrm{SO}}_2$ to ${\mathrm{SO}}_4{}^{2-}$, (c) ${\mathrm{NO}}_2^{-}$ to ${\mathrm{NO}}_3^{-}$, (d) ${\mathrm{H}}_2\mathrm{S}(g)$ to $\mathrm{S}(\mathrm{s})$, (e) ${\mathrm{Fe}}^{2+}$ to ${\mathrm{Fe}}^{3+}$. Write a balanced net ionic equation for each of these redox reactions.

Complete and balance the following equations: (a) ${\mathrm{Li}}_3\mathrm{N}(\mathrm{s})+{\mathrm{H}}_2\mathrm{O}(l)⟶$ (b) ${\mathrm{NH}}_3(aq)+{\mathrm{H}}_2\mathrm{O}(l)⟶$ (c) ${\mathrm{NO}}_2(\mathrm{g})+{\mathrm{H}}_2\mathrm{O}(l)⟶$ (d) ${\mathrm{NH}}_3(g)+{\mathrm{O}}_2(g)\stackrel{\text{ catalyst }}{⟶}$ (e) ${\mathrm{H}}_2{\mathrm{CO}}_3(aq)\stackrel{\mathrm{\Delta }}{⟶}$ (f) $\mathrm{Ni}(s)+\mathrm{CO}(g)⟶$ (h) ${\mathrm{CS}}_2(g)+{\mathrm{O}}_2(g)⟶$ (i) $\mathrm{CaO}(s)+{\mathrm{SO}}_2(g)⟶$ (j) ${\mathrm{CH}}_4(g)+{\mathrm{H}}_2\mathrm{O}(g)\stackrel{\mathrm{\Delta }}{⟶}$ (k) $\mathrm{LiH}(s)+{\mathrm{H}}_2\mathrm{O}(t)⟶$ (1) ${\mathrm{Fe}}_2{\mathrm{O}}_3(s)+3{\mathrm{H}}_2(g)⟶$

The solubility of ${\mathrm{Cl}}_2$ in $100\mathrm{g}$ of water at STP is $310{\mathrm{cm}}^3$. Assume that this quantity of ${\mathrm{Cl}}_2$ is dissolved and equilibrated as follows: $${\mathrm{Cl}}_2(aq)+{\mathrm{H}}_2\mathrm{O}\rightleftharpoons {\mathrm{Cl}}^{-}(aq)+\mathrm{HClO}(aq)+{\mathrm{H}}^{+}(aq)$$ If the equilibrium constant for this reaction is $4.7\times {10}^{-4}$, calculate the equilibrium concentration of $\mathrm{HClO}$ formed.