Question

K3PO4(aq)+Zn(NO3)2(aq) ?

Predict the product of the following reaction and use the proper symbol

Answer 1

Refer to the explanation.

Explanation:

Molecular equation

`"2K"_3"PO"_4("aq") + "3Zn(NO"_3)_2("aq")"` `rarr` `"6KNO"_3("aq") + "Zn"_3"(PO"_4)_2("s")darr"`

The down arrow means that the solid precipitated out of solution. This is a precipitation reaction, which is a type of double replacement reaction (also called a double displacement or metathesis) A precipitate is an insoluble solid that comes from mixing two aqueous solutions.

General form of a double replacement reaction:

`color(red)"A"color(purple)"Y" + color(magenta)"B"color(blue)"X""` `rarr` `color(red)"A"color(blue)"X" + color(magenta)"B"color(purple)"Y"`,

where `color(red)"A"` and `color(magenta)"B"` are cations, and `color(blue)"X"` and `color(purple)"Y"` are anions. In a double replacement reaction, the cations and anions switch partners.

The precipitate `"Zn"_3"(PO"_4)_2("s")"` is the product. The `"K"^(+)("aq")"` and `"NO"_3^(-)("aq")"` ions of `"KNO"_3("aq")"` are dissolved in solution. They are not involved in the reaction and are called spectator ions.

The net ionic equation , which includes only the ions that reacted, is:

`"3Zn"^(2+)("aq") + "2PO"_4^(3-)("aq")` `rarr` `"Zn"_3"(PO"_4)_2("s")darr"`

In order to determine which product, if any, is a precipitate, you need to refer to the solubility rules.