Which of the following compounds when placed in water would produce an electrically conductive solution?

Question

-FeSO4

-ZnBr2

-Mn(OH)2

-CsBr

-CCl4

 

Please select all that are true! 

Answer 1

Some chemistry courses require that student learn rules for predicting solubility.   In the case of Hydroxides, other than the combinations with NH₄+ and the alkali metals, only Barium, Calcium, and Strontium ions form soluble OH compounds.  You are definitely not going to be able to use the Handbook of Chemistry and Physics on an exam.

Answer 2

FeSO4 , ZnBr2 and CsBr are salts reasonably soluble in water.    Mn(OH)2 is not soluble in water.  

Thus FeSO4, ZnBr2 an CsBr dissociate in water producing ions in solution and hence conductive solutions.  Mn(OH)2 does not dissolve - so no ions - very little conductivity.

 

CCl4 does not dissolve well and is not not an ionic compound so does not produce ions in solution.  So no ions, very little conductivity. 

 

Pure water is slightly conductive due to  [H+] =  10^-7  .    However the value is very low. 

 

I had to look up the solubility of Mn(OH)2  on a German language website.

Answer 3

A chemical compound is made up of two or more elements. Compounds can be categorized as either ionic or molecular. Ionic compounds readily dissolve in aqueous solutions and they are good conductors of heat and electricity.

In contrast, molecular compounds are formed from non-metals, and have covalent bonds. In general, molecular compounds do not dissolve readily, and are poor conductors of heat and electricity.

 

So, from the given list, we would expect ZnBr₂, and CsBr to produce electrically conductive solutions.