Question

Will sodium fluoride and calcium nitrate react to produce a precipitate?

Answer 1

There is a precipitate, which is calcium fluoride, `("CaF"_2")`.

Explanation:

Balanced Equation

`"2NaF(aq) + Ca(NO"_3)_2("aq")` `rarr` `"CaF"_2("s") + "2NaNO"_3("aq")"`

As you can see, a precipitate (solid) does form, and it is calcium fluoride `("CaF"_2")`.

This is an example of of a double replacement (double displacement or metathesis) reaction. Evidence of a double replacement reaction include a precipitate, or an insoluble gas must bubble out of solution, or water must be a product (neutralization reaction). The generic equation that represents a double replacement reaction is:

`"AX + BY"` `rarr` `"AY + BX"`

where `"A and B"` are cations, and `"X and Y"` are anions.

There are solubility rules that can help you determine whether a precipitate will form, and what it is. As you can see, fluoride and calcium ions form a solid, as designated by an "s".