# What might you observe when sodium hydroxide solution is added to calcium nitrate solution?

Metathesis of the salts occur to give moderately soluble $C a {\left(O H\right)}_{2} \left(s\right)$:
$C a {\left(N {O}_{3}\right)}_{2} \left(a q\right) + 2 N a O H \left(a q\right) \rightarrow C a {\left(O H\right)}_{2} \left(s\right) \downarrow + 2 N a N {O}_{3} \left(a q\right)$
$\text{Calcium hydroxide}$ is soluble in water to the tune of $1.73 \cdot g \cdot {L}^{-} 1$ at $20$ ""^@C.