Question d3b6a

Jan 10, 2017

Here's what I got.

Explanation:

Barium nitrate, "Ba"("NO"_3)_2, and sodium fluoride, $\text{NaF}$, are soluble ionic compounds, which means that they exist as ions in aqueoues solutions.

${\text{Ba"("NO"_ 3)_ (2(aq)) -> "Ba"_ ((aq))^(2+) + 2"NO}}_{3 \left(a q\right)}^{-}$

${\text{NaF"_ ((aq)) -> "Na"_ ((aq))^(+) + "F}}_{\left(a q\right)}^{-}$

When two aqueous solutions of barium nitrate and sodium fluoride are mixed, two ionic compounds are formed

• barium fluoride, ${\text{BaF}}_{2}$, an insoluble ionic compound that precipitates out of solution
• sodium nitrate, ${\text{NaNO}}_{3}$, a soluble ionic compound that exists as ions in the resulting solution

You can write the unbalanced chemical equation that describes this double replacement reaction like this

${\text{Ba"("NO"_ 3)_ (2(aq)) + "NaF"_ ((aq)) -> "BaF"_ (2(s)) darr + "NaNO}}_{3 \left(a q\right)}$

To balance this chemical equation, add a coefficient of $2$ to sodium fluoride

$\textcolor{\mathrm{da} r k g r e e n}{\underline{\textcolor{b l a c k}{{\text{Ba"("NO"_ 3)_ (2(aq)) + 2"NaF"_ ((aq)) -> "BaF"_ (2(s)) darr + "NaNO}}_{3 \left(a q\right)}}}}$

Now, you can start from the balanced chemical equation and write the complete ionic equation

"Ba"_ ((aq))^(2+) + 2"NO"_ (3(aq))^(-) + 2 xx ["Na"_ ((aq))^(+) + "F"_ ((aq))^(-)] -> "BaF"_ (2(s)) darr + 2 xx ["Na"_ ((aq))^(+) + "NO"_ (3(aq))^(-)]

This is equivalent to

${\text{Ba"_ ((aq))^(2+) + 2"NO"_ (3(aq))^(-) + 2"Na"_ ((aq))^(+) + 2"F"_ ((aq))^(-) -> "BaF"_ (2(s)) darr + 2"Na"_ ((aq))^(+) + 2"NO}}_{3 \left(a q\right)}^{-}$

In order to get the net ionic equation, you must remove the spectator ions, i.e. the ions that are present on both sides of the equation.

"Ba"_ ((aq))^(2+) + color(red)(cancel(color(black)(2"NO"_ (3(aq))^(-)))) + color(red)(cancel(color(black)(2"Na"_ ((aq))^(+)))) + 2"F"_ ((aq))^(-) -> "BaF"_ (2(s)) darr + color(red)(cancel(color(black)(2"Na"_ ((aq))^(+)))) + color(red)(cancel(color(black)(2"NO"_ (3(aq))^(-))))#

This will get you

$\textcolor{\mathrm{da} r k g r e e n}{\underline{\textcolor{b l a c k}{{\text{Ba"_ ((aq))^(2+) + 2"F"_ ((aq))^(-) -> "BaF}}_{2 \left(s\right)} \downarrow}}}$