Write and balance the following word reactions, and state if a precipitate is formed? Barium cyanide reacts with ammonium sulfate. Potassium hydroxide reacts with magnesium chloride.
1 Answer
These are regular double-replacement reactions, of the form
#AB + CD -> AD + CB# .
Basically, the cations switch, and charge is considered when determining the number of anions per cation / cations per anion. What is the formed solid called?
So, you should get:
#color(blue)(stackrel(color(red)(2+))"Ba"(stackrel(color(red)(1-))"CN")_2(aq) + (stackrel(color(red)(1+))("NH"_4))_2stackrel(color(red)(2-))("SO"_4)(aq) -> 2stackrel(color(red)(1+))("NH"_4)stackrel(color(red)(1-))("CN")(aq) + stackrel(color(red)(2+))"Ba"stackrel(color(red)(2-))("SO"_4)(s))#
Is this balanced? If not, you should fix it up.
-
Barium cyanide is reasonably soluble in water (
#"18 g/100 mL water"# at#25^@ "C"# ). -
Barium sulfate is very poorly soluble (as we would expect from the guideline that sulfates are soluble except for those with
#"Ag"^(+)# ,#"Pb"^(2+)# ,#"Ca"^(2+)# ,#"Sr"^(2+)# , or#"Ba"^(2+)# cations). -
All ammonium-based compounds are very soluble.
#color(blue)(2stackrel(color(red)(1+))"K"stackrel(color(red)(1-))"OH"(aq) + stackrel(color(red)(2+))"Mg"stackrel(color(red)(1-))("Cl"_2)(aq) -> 2stackrel(color(red)(1+))"K"stackrel(color(red)(1-))"Cl"(aq) + stackrel(color(red)(2+))"Mg"(stackrel(color(red)(1-))"OH")_2(s))#
Is this balanced? If not, you should fix it up.
- All alkali-metal-based compounds are quite soluble in water.
- Halides are as well (except for those with
#"Hg"_2^(2+)# ,#"Ag"^(+)# , or#"Pb"^(2+)# cations). - Hydroxides tend to be insoluble, and
#"Mg"("OH")_2# is no exception (#"0.00064 g/100 mL water"# at#25^@ "C"# ).
