Chapter 3, Problem 134QRT

Interpretation Introduction

Interpretation:

An unknown solution contains either calcium ions or strontium ions. The solution has ${\text{Ca}}^{\text{2+}}{\text{or Sr}}^{\text{2+}}$ ions has to be identified.

Concept introduction:

Soluble compounds in water:

All group  ${\text{1A (Li}}^{\text{+}}{\text{, Na}}^{\text{+}}{\text{, K}}^{\text{+}}{\text{, Rb}}^{\text{+}}{\text{, Cs}}^{\text{+}}\text{)}$ and ${\text{NH}}_4^{+}$ compound are soluble, all nitrates $\left({\text{NO}}_{\text{3}}{}^{\text{-}}\right)$ are soluble.

Almost all the salts of ${\text{Cl}}^{\text{-}}{\text{, Br}}^{\text{-}}{\text{, I}}^{\text{-}}\left(\text{halides}\right)$ are soluble. But some of the halides namely  ${\text{Ag}}^{\text{+}}{\text{, Hg}}_{\text{2}}{}^{\text{2+}}{\text{, Pb}}^{\text{2+}}$ are insoluble.

Most of the sulfates are soluble except ${\text{CaSO}}_{\text{4}}{\text{, SrSO}}_{\text{4}}{\text{, BaSO}}_{\text{4}}{\text{ and PbSO}}_{\text{4}}$ are insoluble.

All the chlorate $\left({\text{ClO}}_{\text{3}}{}^{\text{-}}\right)$, perchlorate $\left({\text{ClO}}_{\text{4}}{}^{\text{-}}\right)$, acetate $\left({\text{CH}}_{\text{3}}{\text{CO}}_{\text{2}}{}^{\text{-}}\right)$ are soluble.

Salts of F^- are soluble. But some of the fluoride salt of ${\text{Mg}}^{\text{2+}}{\text{, Ca}}^{\text{2+}}{\text{, Sr}}^{\text{2+}}{\text{, Ba}}^{\text{2+}}{\text{, Pb}}^{\text{2+}}$ are insoluble.

Salts of $\text{sulfate }\left({\text{SO}}_{\text{4}}{}^{\text{2-}}\right)$ are soluble. But sulfates of ${\text{Ca}}^{\text{2+}}{\text{, Sr}}^{\text{2+}}{\text{, Ba}}^{\text{2+}}{\text{, Pb}}^{\text{2+}}{\text{, Ag}}^{\text{+}}$ are insoluble.

Insoluble compounds in water:

All phosphates $\left({\text{PO}}_{\text{4}}{}^{\text{3-}}\right)$ and carbonates $\left({\text{CO}}_{\text{3}}{}^{\text{2-}}\right)$ are insoluble except ${\text{NH}}_4^{+}$ and Group ${\text{1A (Li}}^{\text{+}}{\text{, Na}}^{\text{+}}{\text{, K}}^{\text{+}}{\text{, Rb}}^{\text{+}}{\text{, Cs}}^{\text{+}}\text{)}$.

All chromates $\left({\text{CrO}}_{\text{4}}{}^{\text{2-}}\right)$ are insoluble except ${\text{NH}}_4^{+}$,  ${\text{Mg}}^{\text{2+}}$ and Group ${\text{1A (Li}}^{\text{+}}{\text{, Na}}^{\text{+}}{\text{, K}}^{\text{+}}{\text{, Rb}}^{\text{+}}{\text{, Cs}}^{\text{+}}\text{)}$.

All hydroxides are insoluble except ${\text{NH}}_4^{+}$,  ${\text{Mg}}^{\text{2+}}$ and Group ${\text{1A (Li}}^{\text{+}}{\text{, Na}}^{\text{+}}{\text{, K}}^{\text{+}}{\text{, Rb}}^{\text{+}}{\text{, Cs}}^{\text{+}}\text{)}$. $\text{Sr}{\left(\text{OH}\right)}_{\text{2}}\text{, Ba}{\left(\text{OH}\right)}_{\text{2}}\text{, and Ca}{\left(\text{OH}\right)}_{\text{2}}$ are slightly soluble.

All oxalates $\left({\text{C}}_{\text{2}}{\text{O}}_{\text{4}}{}^{\text{2-}}\right)$ are insoluble except ${\text{NH}}_4^{+}$ and Group ${\text{1A (Li}}^{\text{+}}{\text{, Na}}^{\text{+}}{\text{, K}}^{\text{+}}{\text{, Rb}}^{\text{+}}{\text{, Cs}}^{\text{+}}\text{)}$.

All sulfides $\left({\text{S}}^{\text{2-}}\right)$ are insoluble except ${\text{NH}}_4^{+}$ and Group ${\text{1A (Li}}^{\text{+}}{\text{, Na}}^{\text{+}}{\text{, K}}^{\text{+}}{\text{, Rb}}^{\text{+}}{\text{, Cs}}^{\text{+}}\text{)}$ and Group 2A ($\text{MgS, CaS, and BaS}$ are sparingly soluble).

Most of the metal hydroxides and oxides are insoluble in water bit some of the alkali metal hydroxides, $\text{Ba}{\left(\text{OH}\right)}_{\text{2}}\text{and Sr}{\left(\text{OH}\right)}_{\text{2}}$ are soluble in water.