Question

what is the net ionic equation for the reaction between calcium nitrate and sodium sulfate?
\\(\ce{ca^{2+} + 2no^{-}_{3} + 2na^{+} + so^{2-}_{4} -> caso_{4} + 2na^{+} + no^{-}_{3}}\\)
\\(\ce{ca^{2+} + so^{2-}_{4} -> caso_{4}}\\)
\\(\ce{ca(no_{3})_{2} + na_{2}so_{4} -> caso_{4} + 2nano_{3}}\\)
no reaction exists

Explanation:

Step1: Identify reactants and products

The reactants are calcium nitrate ($\ce{Ca(NO3)2}$) and sodium sulfate ($\ce{Na2SO4}$). When they dissociate in solution:
$\ce{Ca(NO3)2 -> Ca^{2+} + 2NO3^-}$
$\ce{Na2SO4 -> 2Na^+ + SO4^{2-}}$
The products are calcium sulfate ($\ce{CaSO4}$) and sodium nitrate ($\ce{NaNO3}$). Sodium nitrate is soluble, so its ions ($\ce{Na^+}$ and $\ce{NO3^-}$) are spectator ions.

Step2: Write net ionic equation

Spectator ions (ions that appear on both sides) are removed. So we remove $\ce{Na^+}$ and $\ce{NO3^-}$, leaving the reaction between $\ce{Ca^{2+}}$ and $\ce{SO4^{2-}}$ to form $\ce{CaSO4}$:
$\ce{Ca^{2+} + SO4^{2-} -> CaSO4}$

Answer:

B. $\ce{Ca^{2+} + SO4^{2-} -> CaSO4}$