How do we prepare a #100*mL# of a #0.010*mol*L^-1# solution of #Fe^(2+)# in aqueous solution...?

1 Answer
Jun 6, 2017

Answer:

If we use #"Mohr's salt"#, #(NH _4) _2 Fe(SO_4)_2 *6H_2O# whose molar mass is #392.13* g* mol^-1#. We need approx. #4*g# to prepare such a solution.

Explanation:

A #0.10*N# solution #-=# #0.10*mol*L^-1# is required.

Which, given a volume of #100*mL# constitutes a molar quantity of....

#-=0.10*mol*L^-1xx100xx10^-3*L=0.010*mol#

Which constitutes a mass of................

#0.010*molxx392.13*g*mol^-1=3.921*g#

Note that #"Mohr's salt"# is the standard #Fe(+II)# salt used in the laboratory, as it is stable with respect to oxidation.