The molecular formula of a commercial resin used for exchanging ions in water softening is #"C"_8"H"_7("SO"_3)"Na"# molecular weight 206. The maximum uptake of #"Ca"^(2+)# ions by the resin when expressed in mole per gram resin is?

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Answer 1 · 2017-09-09T16:29:54

Balanced equation for water softening can be written as

#2"C"_8"H"_7("SO"_3)"Na"+"Ca"^(2+)->("C"_8"H"_7("SO"_3))_2"Ca"+2"Na"^(+)#

From the equation we see that #2# moles of resin require #1# mole of #"Ca"^(2+)#

Given is molecular weight of resin #=206#.
#412# g of resin require #1# mole of #"Ca"^(2+)#
#:.# Maximum uptake of #"Ca"^(2+)# is #=1/(412)#

#~~0.0024# moles/g of resin