Problem 3
(a) Write an equation to show how Mg reacts with \(\mathrm{N}_{2}\) when heated. (b) Suggest how the product reacts with water.
Problem 5
Write balanced equations for the following reactions: (a) the thermal decomposition of \(\left[\mathrm{NH}_{4}\right]_{2}\left[\mathrm{BeF}_{4}\right]\) (b) the reaction between \(\mathrm{NaCl}\) and \(\mathrm{BeCl}_{2}\) (c) the dissolution of BeF \(_{2}\) in water.
Problem 9
(a) How do anhydrous \(\mathrm{CaCl}_{2}\) and \(\mathrm{CaH}_{2}\) function as drying agents? (b) Compare the solid state structures and properties of \(\mathrm{BeCl}_{2}\) and \(\mathrm{CaCl}_{2}\)
Problem 13
(a) What qualitative test is used for \(\mathrm{CO}_{2} ?\) (b) What reaction takes place, and (c) what is observed in a positive test?
Problem 15
Write a short account that justifies the so-called diagonal relationship between Li and Mg.
Problem 20
Comment on the following statements. (a) \(\mathrm{Na}_{2} \mathrm{S}\) adopts a solid state structure that is related to that of CaF \(_{2}\) (b) \(\left[\mathrm{C}_{3}\right]^{4}, \mathrm{CO}_{2}\) and \(\left[\mathrm{CN}_{2}\right]^{2-}\) are isoelectronic species. (c) \(\operatorname{Be}(\mathrm{OH})_{2}\) is virtually insoluble in water, but is soluble in aqueous solutions containing excess hydroxide ions. (d) \(\mathrm{MgO}\) is used as a refractory material.
Problem 21
Suggest products for the following reactions, and write balanced equations for the reactions. Comment on any of these reactions that are important in chemical manufacturing processes. (a) \(\mathrm{CaH}_{2}+\mathrm{H}_{2} \mathrm{O}-\) (b) \(\mathrm{BeCl}_{2}+\mathrm{LiAlH}_{4}-=\) (c) \(\mathrm{CaC}_{2}+\mathrm{H}_{2} \mathrm{O}--\) (d) \(\mathrm{BaO}_{2}+\mathrm{H}_{2} \mathrm{SO}_{4}--\) (c) \(\mathrm{CaF}_{2}+\mathrm{H}_{2} \mathrm{SO}_{4}(\mathrm{conc}) \rightarrow\) \((f) M g O+H_{2} O_{2}--\) \((\mathrm{g}) \mathrm{MgCO}_{3} \stackrel{\Delta}{\longrightarrow}\) (h) \(\mathrm{Mg}\) in air \(\Delta\)
Problem 22
(a) \(\mathrm{A}\) group 2 metal, \(\mathrm{M}\), dissolves in liquid \(\mathrm{NH}_{3}\), and from the solution, compound \(\mathbf{A}\) can be isolated. A slowly decomposes to B with liberation of \(\mathrm{NH}_{3}\) and a gas \(\mathrm{C}\) Metal \(\mathbf{M}\) gives a crimson flame test; through blue glass, the flame appears pale purple. Suggest identities for \(\mathbf{M}, \mathbf{A}, \mathbf{B}\) and \(\mathbf{C}\) (b) The group 2 metal \(\mathbf{X}\) occurs naturally in great abundance as the carbonate. Metal X reacts with cold water, forming compound \(\mathbf{D}\), which is a strong base. Aqueous solutions of \(\mathbf{D}\) are used in qualitative tests for \(\mathrm{CO}_{2} .\) X combines with \(\mathrm{H}_{2}\) to give a saline hydride that is used as a drying agent. Identify \(\mathbf{X}\) and \(\mathbf{D}\). Write equations for the reaction of \(\mathbf{X}\) with \(\mathrm{H}_{2} \mathrm{O}\) and of the hydride of \(\mathbf{X}\) with \(\mathrm{H}_{2} \mathrm{O}\). Explain how you would carry out a qualitative test for \(\mathrm{CO}_{2}\) using an aqueous solution of \(\mathbf{D}\)
Problem 23
(a) \(A\) 6-coordinate complex may be obtained by crystallizing anhydrous CaI \(_{2}\) from THF solution at \(253 \mathrm{K}\). In contrast, when anhydrous \(\mathrm{Bal}_{2}\) is crystallized from THF at \(253 \mathrm{K},\) a 7 -coordinate complex is isolated. Suggest structures for the two complexes, and comment on possible isomerism and factors that may favour one particular isomer in each case. Rationalize why \(\mathrm{CaI}_{2}\) and \(\mathrm{BaI}_{2}\) form complexes with THF that have different coordination numbers. (b) Which of the following compounds are sparingly soluble in water, which are soluble without reaction, and which react with water: \(\mathrm{BaSO}_{4}, \mathrm{CaO}, \mathrm{MgCO}_{3}\) \(\mathrm{Mg}(\mathrm{OH})_{2}, \mathrm{SrH}_{2}, \mathrm{BeCl}_{2}, \mathrm{Mg}\left(\mathrm{ClO}_{4}\right)_{2}, \mathrm{CaF}_{2}, \mathrm{BaCl}_{2}\) \(\mathrm{Ca}\left(\mathrm{NO}_{3}\right)_{2} ?\) For the compounds that react with water, what are the products formed?
