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?

1 Answer
Jan 18, 2017


A metathesis, or partner exchange reaction has occurred:


#2AgNO_3(aq) + Na_2CrO_4(aq) rarr 2AgNO_3(aq) + Ag_2CrO_4(s)#

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 #"precipitation reaction"#. This particular reaction is the basis of the #"Mohr titration"#, for quantitative analysis of silver ion.