# A student combines solutions of silver nitrate, AgNO_3, and sodium chromate, Na_2CrO_4, and observes that a reddish-brown solid forms. Based on this observation, what type of a reaction can the student infer has occurred?

Jan 18, 2017

#### Answer:

A metathesis, or partner exchange reaction has occurred:

#### Explanation:

$2 A g N {O}_{3} \left(a q\right) + N {a}_{2} C r {O}_{4} \left(a q\right) \rightarrow 2 A g N {O}_{3} \left(a q\right) + A {g}_{2} C r {O}_{4} \left(s\right)$

Most silver salts are quite insoluble; the nitrate is an exception. Silver chromate precipitates from aqueous solution as a brick red precipitate.

The reaction could also be called a $\text{precipitation reaction}$. This particular reaction is the basis of the $\text{Mohr titration}$, for quantitative analysis of silver ion.