Following are some laboratory methods occasionally used for the preparation of small quantities of chemicals. Write a balanced equation for each. (a) preparation of \(\mathrm{H}_{2} \mathrm{S}(\mathrm{g}): \mathrm{HCl}(\mathrm{aq})\) is heated with \(\mathrm{FeS}(\mathrm{s})\) (b) preparation of \(\mathrm{Cl}_{2}(\mathrm{g}): \mathrm{HCl}(\mathrm{aq})\) is heated with \(\mathrm{MnO}_{2}(\mathrm{s}) ; \mathrm{MnCl}_{2}(\mathrm{aq})\) and \(\mathrm{H}_{2} \mathrm{O}(1)\) are other products (c) preparation of \(\mathrm{N}_{2}: \mathrm{Br}_{2}\) and \(\mathrm{NH}_{3}\) react in aqueous solution; \(\mathrm{NH}_{4} \mathrm{Br}\) is another product (d) preparation of chlorous acid: an aqueous suspension of solid barium chlorite is treated with dilute \(\mathrm{H}_{2} \mathrm{SO}_{4}(\mathrm{aq})\)

Short Answer

Expert verified
The balanced chemical equations are: (a) FeS(s) + 2HCl(aq) → H2S(g) + FeCl2(aq), (b) 4HCl(aq) + MnO2(s) → Cl2(g) + MnCl2(aq) + 2H2O(l), (c) 8NH3 + 3Br2 → N2 + 6NH4Br, and (d) Ba(ClO2)2 + H2SO4 → 2HClO2 + BaSO4(s).

Step by step solution

01

Preparation of H2S(g)

HCl(aq) and FeS(s) react to form H2S(g) and a by-product, FeCl2(s). As per stoichiometry, one molecule of HCl reacts with one molecule of FeS to produce one molecule of H2S and one molecule of FeCl2. Therefore, the balanced chemical equation is: \\[FeS(s) + 2HCl(aq) \longrightarrow H2S(g) + FeCl2(aq)\]
02

Preparation of Cl2(g)

When HCl(aq) is heated with MnO2(s), it leads to the formation of Cl2(g), MnCl2(aq) and H2O(l). Balancing the equation yields: \\[4HCl(aq) + MnO2(s) \longrightarrow Cl2(g) + MnCl2(aq) + 2H2O(l)\]
03

Preparation of N2

NH3 and Br2 react to form N2 and NH4Br. Balancing the equation gives: \\[8NH3 + 3Br2 \longrightarrow N2 + 6NH4Br\]
04

Preparation of chlorous acid

When an aqueous suspension of barium chlorite is treated with dilute H2SO4(aq), chlorous acid and barium sulfate are formed. The balanced equation for this reaction is: \\[Ba(ClO2)2 + H2SO4 \rightarrow 2HClO2 + BaSO4(s)\]

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Most popular questions from this chapter

Explain the important distinctions between (a) a strong electrolyte and strong acid; (b) an oxidizing agent and reducing agent; (c) precipitation reactions and neutralization reactions; (d) half-reaction and overall reaction.

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