Question #370a7

1 Answer
Jun 26, 2015

Answer:

#Pb_((aq))^(2+)+2OH_((aq))^(-)rarrPb(OH)_(2(s))#

Explanation:

By #NH_3# I am assuming you mean ammonia solution.

This partly ionises in water to give ammonium and hydroxide ions:

#NH_(3(g))+H_2O_((l))rightleftharpoonsNH_(4(aq))^(+)+OH_((aq))^(-)#

A white precipitate of lead(II) hydroxide is formed if aqueous lead(II) ions are added:

#Pb_((aq))^(2+)+2OH_((aq))^(-)rarrPb(OH)_(2(s))#

The same reaction happens with #NaOH# solution.

The sodium ions remain in solution as spectator ions.

If XS sodium hydroxide is added the precipitate redissolves to give the soluble plumbate(II) ion.

A simple way of writing this is:

www.chemguide.co.uk

(chemguideUK)

Ammonia solution can't do this as the concentration of #OH^(-)# ions is not high enough.