Chapter 8, Problem 44A

Interpretation Introduction

Interpretation:

The given table has to be completed with the formulas for the precipitates that would form.

Concept introduction:

A precipitation reaction is the reaction in which dissolved substances react to form one or more solid products. Precipitates are formed when an insoluble compound is produced in the reaction.

For example :

  $solution(aq)+solution(aq)\to solid(s)$

Aqueous solution is soluble is water and the solid formed is called precipitate.

Answer to Problem 44A

	$C_2{H}_3{O}_2{}^{-}$	$C{l}^{-}$	$C{O}_3{}^{2-}$	$N{O}_3{}^{-}$	$O{H}^{-}$	$P{O}_4{}^{3-}$	$S^{2-}$	$S{O}_4{}^{2-}$
$A{g}^{+}$	No PPT	AgCl	$A{g}_{2}C{O}_3$	No PPT	$AgOH$	$A{g}_{3}P{O}_4$	$Ag{S}_2$	$A{g}_{2}S{O}_4$
$B{a}^{2+}$	No PPT	No PPT	$BaC{O}_3$	No PPT	No PPT	$B{a}_3{(P{O}_4)}_2$	No PPT	$BaS{O}_4$
$C{a}^{2+}$	No PPT	No PPT	$CaC{O}_3$	No PPT	No PPT	$C{a}_3{(P{O}_4)}_2$	No PPT	$CaS{O}_4$
$F{e}^{3+}$	No PPT	No PPT	$F{e}_2{(C{O}_3)}_3$	No PPT	$F{e}_2{(OH)}_3$	$FeP{O}_4$	$F{e}_2{S}_3$	No PPT
$H{g}_2{}^{2+}$	No PPT	$H{g}_{2}C{l}_2$	$H{g}_{2}C{O}_3$	No PPT	$H{g}_2{(OH)}_2$	${(H{g}_2)}_3{(P{O}_4)}_2$	$H{g}_{2}S$	$H{g}_{2}S{O}_4$
$N{a}^{+}$	No PPT	No PPT	No PPT	No PPT	No PPT	No PPT	No PPT	No PPT
$N{i}^{2+}$	No PPT	No PPT	$NiC{O}_3$	No PPT	$Ni{(OH)}_2$	$N{i}_3{(P{O}_4)}_2$	$NiS$	No PPT
$P{b}^{2+}$	No PPT	$PbC{l}_2$	$PbC{O}_3$	No PPT	$Pb{(OH)}_2$	$P{b}_3{(P{O}_4)}_2$	$PbS$	$PbS{O}_4$

According to the solubility rules,

1. All alkali metal compounds are soluble (Li, Na, K, Rb, Cs)
2. All $N{O}_3{}^{-}$ , $Cl{O}_3{}^{-},Cl{O}_4{}^{-},$ $C_2{H}_3{O}_2{}^{-}$$areso\mathrm{lub}le$ .
3. All $N{H}_4{}^{+}compoundsareso\mathrm{lub}le.$(NH₄OH, NH₄Cl) .
4. All $C{l}^{-},B{r}^{-},I^{-}compoundsareso\mathrm{lub}le.$ (except for $A{g}^{+}$ , $H{g}_2{}^{2+}$ , $P{b}^{2+}$$)$ .
5. All $S{O}_4{}^{2-}$$compoundsareso\mathrm{lub}le.$ (except for $B{a}^{2+}$ , $C{a}^{2+}$ , $S{r}^{2+}$ , $P{b}^{2+}$ , $H{g}_2{}^{2+}$ , $A{g}^{+}$  $)$
6. All $O{H}^{-}$$compoundsareinso\mathrm{lub}le$ ,(except for $B{a}^{2+}$ , $C{a}^{2+}$ , $S{r}^{2+}$ , alkali metals, $N{H}_4{}^{+}$)
7. All $S^{2-}$$compoundsareinso\mathrm{lub}le$,(except for alkali metals and alkaline earth metals.)
8. All $S{O}_3{}^{2-},C{O}_3{}^{2-},Cr{O}_4{}^{2-},$$P{O}_4{}^{3-}$$compoundsareinso\mathrm{lub}le$ , except for $N{H}_4{}^{+}$, alkali metals)

According to the solubility rule no.4, all Cl- are soluble except for $A{g}^{+}$ , $H{g}_2{}^{2+}$ , $P{b}^{2+}$ , that is they form precipitates.

  $A{g}^{+}(aq)+C{l}^{-}(aq)\to AgCl(s)$

  $H{g}_2{}^{2+}(aq)+2C{l}^{-}(aq)\to H{g}_{2}C{l}_2(s)$

  $P{b}^{2+}(aq)+2C{l}^{-}(aq)\to PbC{l}_2(s)$

According to rule no.7, all carbonates ( $C{O}_3{}^{2-}$ ) are insoluble except for alkali metals (Li, Na, K, Rb, Cs)

  $2A{g}^{+}(aq)+C{O}_3{}^{2-}(aq)\to A{g}_{2}C{O}_3(s)$

  $B{a}^{2+}(aq)+C{O}_3{}^{2-}(aq)\to BaC{O}_3(s)$

  $C{a}^{2+}(aq)+C{O}_3{}^{2-}(aq)\to CaC{O}_3(s)$

  $H{g}_2{}^{2+}(aq)+C{O}_3{}^{2-}(aq)\to H{g}_{2}C{O}_3(s)$

  $N{i}^{2+}(aq)+C{O}_3{}^{2-}(aq)\to NiC{O}_3(s)$

  $P{b}^{2+}(aq)+C{O}_3{}^{2-}(aq)\to PbC{O}_3(s)$

According to rule no.2, all nitrates are soluble. So no precipitate is formed from the given ions.

According to rule no.6, all $O{H}^{-}$$compoundsareinso\mathrm{lub}le$ ,(except for $B{a}^{2+}$ , $C{a}^{2+}$ , $S{r}^{2+}$ , alkali metals, $N{H}_4{}^{+}$ )

  $A{g}^{+}(aq)+O{H}^{-}(aq)\to AgOH(s)$

  $2F{e}^{3+}(aq)+3O{H}^{-}(aq)\to F{e}_2{(OH)}_3(s)$

  $H{g}_2{}^{2+}(aq)+2O{H}^{-}(aq)\to H{g}_2{(OH)}_2(s)$

  $N{i}^{2+}(aq)+2O{H}^{-}(aq)\to Ni{(OH)}_2(s)$

  $P{b}^{2+}(aq)+2O{H}^{-}(aq)\to Pb{(OH)}_2(s)$

According to rule no.8, all phosphates ( $P{O}_4{}^{3-}$ ) are insoluble except for alkali metals, which is alkali metals (Na+ in this case) do not form precipitates.

  $3A{g}^{+}(aq)+P{O}_4{}^{3-}(aq)\to A{g}_{3}P{O}_4(s)$

  $3B{a}^{2+}(aq)+2P{O}_4{}^{3-}(aq)\to B{a}_3{(P{O}_4)}_2(s)$

  $3C{a}^{2+}(aq)+2P{O}_4{}^{3-}(aq)\to C{a}_3{(P{O}_4)}_2(s)$

  $F{e}^{3+}(aq)+P{O}_4{}^{3-}(aq)\to FeP{O}_4(s)$

  $3H{g}_2{}^{2+}(aq)+2P{O}_4{}^{3-}(aq)\to {(H{g}_2)}_3{(P{O}_4)}_2(s)$

  $3N{i}^{2+}(aq)+2P{O}_4{}^{3-}(aq)\to N{i}_3{(P{O}_4)}_2(s)$

  $3P{b}^{2+}(aq)+2P{O}_4{}^{3-}(aq)\to P{b}_3{(P{O}_4)}_2(s)$

According to rule no.7, all $S^{2-}$$compoundsareinso\mathrm{lub}le$ , except for alkali metals and alkaline earth metals (Be, Mg, Ca, Sr, Ba,) that is, they don’t form precipitates.

  $2A{g}^{+}(aq)+S^{2-}(aq)\to Ag{S}_2(s)$

  $2F{e}^{3+}(aq)+3S^{2-}(aq)\to F{e}_2{S}_3(s)$

  $H{g}_2{}^{2+}(aq)+S^{2-}(aq)\to H{g}_{2}S(s)$

  $N{i}^{2+}(aq)+S^{2-}(aq)\to NiS(s)$

  $P{b}^{2+}(aq)+S^{2-}(aq)\to PbS(s)$

According to rule no.5, all sulphates , $S{O}_4{}^{2-}$$compoundsareso\mathrm{lub}le.$ (Except for $B{a}^{2+}$ , $C{a}^{2+}$ , $S{r}^{2+}$ , $P{b}^{2+}$ , $H{g}_2{}^{2+}$ , $A{g}^{+}$ that is, these will form precipitates.

  $2A{g}^{+}(aq)+S{O}_4{}^{2-}(aq)\to A{g}_{2}S{O}_4(s)$

  $B{a}^{2+}(aq)+S{O}_4{}^{2-}(aq)\to BaS{O}_4(s)$

  $H{g}_2{}^{2+}(aq)+S{O}_4{}^{2-}(aq)\to H{g}_{2}S{O}_4(s)$

  $C{a}^{2+}(aq)+S{O}_4{}^{2-}(aq)\to CaS{O}_4(s)$

  $P{b}^{2+}(aq)+S{O}_4{}^{2-}(aq)\to PbS{O}_4(s)$

Explanation of Solution

According to the solubility rules,

1. All alkali metal compounds are soluble (Li, Na, K, Rb, Cs)
2. All $N{O}_3{}^{-}$ , $Cl{O}_3{}^{-},Cl{O}_4{}^{-},$ $C_2{H}_3{O}_2{}^{-}$$areso\mathrm{lub}le$ .
3. All $N{H}_4{}^{+}compoundsareso\mathrm{lub}le.$(NH₄OH, NH₄Cl) .
4. All $C{l}^{-},B{r}^{-},I^{-}compoundsareso\mathrm{lub}le.$ (except for $A{g}^{+}$ , $H{g}_2{}^{2+}$ , $P{b}^{2+}$$)$ .
5. All $S{O}_4{}^{2-}$$compoundsareso\mathrm{lub}le.$ (except for $B{a}^{2+}$ , $C{a}^{2+}$ , $S{r}^{2+}$ , $P{b}^{2+}$ , $H{g}_2{}^{2+}$ , $A{g}^{+}$  $)$
6. All $O{H}^{-}$$compoundsareinso\mathrm{lub}le$ ,(except for $B{a}^{2+}$ , $C{a}^{2+}$ , $S{r}^{2+}$ , alkali metals, $N{H}_4{}^{+}$)
7. All $S^{2-}$$compoundsareinso\mathrm{lub}le$,(except for alkali metals and alkaline earth metals.)
8. All $S{O}_3{}^{2-},C{O}_3{}^{2-},Cr{O}_4{}^{2-},$$P{O}_4{}^{3-}$$compoundsareinso\mathrm{lub}le$ , except for $N{H}_4{}^{+}$, alkali metals)

According to the solubility rule no.4, all Cl- are soluble except for $A{g}^{+}$ , $H{g}_2{}^{2+}$ , $P{b}^{2+}$ , that is they form precipitates.

  $A{g}^{+}(aq)+C{l}^{-}(aq)\to AgCl(s)$

  $H{g}_2{}^{2+}(aq)+2C{l}^{-}(aq)\to H{g}_{2}C{l}_2(s)$

  $P{b}^{2+}(aq)+2C{l}^{-}(aq)\to PbC{l}_2(s)$

According to rule no.7, all carbonates ( $C{O}_3{}^{2-}$ ) are insoluble except for alkali metals (Li, Na, K, Rb, Cs)

  $2A{g}^{+}(aq)+C{O}_3{}^{2-}(aq)\to A{g}_{2}C{O}_3(s)$

  $B{a}^{2+}(aq)+C{O}_3{}^{2-}(aq)\to BaC{O}_3(s)$

  $C{a}^{2+}(aq)+C{O}_3{}^{2-}(aq)\to CaC{O}_3(s)$

  $H{g}_2{}^{2+}(aq)+C{O}_3{}^{2-}(aq)\to H{g}_{2}C{O}_3(s)$

  $N{i}^{2+}(aq)+C{O}_3{}^{2-}(aq)\to NiC{O}_3(s)$

  $P{b}^{2+}(aq)+C{O}_3{}^{2-}(aq)\to PbC{O}_3(s)$

According to rule no.2, all nitrates are soluble. So no precipitate is formed from the given ions.

According to rule no.6, all $O{H}^{-}$$compoundsareinso\mathrm{lub}le$ ,(except for $B{a}^{2+}$ , $C{a}^{2+}$ , $S{r}^{2+}$ , alkali metals, $N{H}_4{}^{+}$ )

  $A{g}^{+}(aq)+O{H}^{-}(aq)\to AgOH(s)$

  $2F{e}^{3+}(aq)+3O{H}^{-}(aq)\to F{e}_2{(OH)}_3(s)$

  $H{g}_2{}^{2+}(aq)+2O{H}^{-}(aq)\to H{g}_2{(OH)}_2(s)$

  $N{i}^{2+}(aq)+2O{H}^{-}(aq)\to Ni{(OH)}_2(s)$

  $P{b}^{2+}(aq)+2O{H}^{-}(aq)\to Pb{(OH)}_2(s)$

According to rule no.8, all phosphates ( $P{O}_4{}^{3-}$ ) are insoluble except for alkali metals, which is alkali metals (Na+ in this case) do not form precipitates.

  $3A{g}^{+}(aq)+P{O}_4{}^{3-}(aq)\to A{g}_{3}P{O}_4(s)$

  $3B{a}^{2+}(aq)+2P{O}_4{}^{3-}(aq)\to B{a}_3{(P{O}_4)}_2(s)$

  $3C{a}^{2+}(aq)+2P{O}_4{}^{3-}(aq)\to C{a}_3{(P{O}_4)}_2(s)$

  $F{e}^{3+}(aq)+P{O}_4{}^{3-}(aq)\to FeP{O}_4(s)$

  $3H{g}_2{}^{2+}(aq)+2P{O}_4{}^{3-}(aq)\to {(H{g}_2)}_3{(P{O}_4)}_2(s)$

  $3N{i}^{2+}(aq)+2P{O}_4{}^{3-}(aq)\to N{i}_3{(P{O}_4)}_2(s)$

  $3P{b}^{2+}(aq)+2P{O}_4{}^{3-}(aq)\to P{b}_3{(P{O}_4)}_2(s)$

According to rule no.7, all $S^{2-}$$compoundsareinso\mathrm{lub}le$ , except for alkali metals and alkaline earth metals (Be, Mg, Ca, Sr, Ba,) that is, they don’t form precipitates.

  $2A{g}^{+}(aq)+S^{2-}(aq)\to Ag{S}_2(s)$

  $2F{e}^{3+}(aq)+3S^{2-}(aq)\to F{e}_2{S}_3(s)$

  $H{g}_2{}^{2+}(aq)+S^{2-}(aq)\to H{g}_{2}S(s)$

  $N{i}^{2+}(aq)+S^{2-}(aq)\to NiS(s)$

  $P{b}^{2+}(aq)+S^{2-}(aq)\to PbS(s)$

According to rule no.5, all sulphates , $S{O}_4{}^{2-}$$compoundsareso\mathrm{lub}le.$ (Except for $B{a}^{2+}$ , $C{a}^{2+}$ , $S{r}^{2+}$ , $P{b}^{2+}$ , $H{g}_2{}^{2+}$ , $A{g}^{+}$ that is, these will form precipitates.

  $2A{g}^{+}(aq)+S{O}_4{}^{2-}(aq)\to A{g}_{2}S{O}_4(s)$

  $B{a}^{2+}(aq)+S{O}_4{}^{2-}(aq)\to BaS{O}_4(s)$

  $H{g}_2{}^{2+}(aq)+S{O}_4{}^{2-}(aq)\to H{g}_{2}S{O}_4(s)$

  $C{a}^{2+}(aq)+S{O}_4{}^{2-}(aq)\to CaS{O}_4(s)$

  $P{b}^{2+}(aq)+S{O}_4{}^{2-}(aq)\to PbS{O}_4(s)$