The molecular formula of a commercial resin used for exchanging ions in water softening is C8H7SO3Na (molecular weight = 206). What would be the maximum uptake of Ca2+ ions by the resin when expressed in mole per gram resin?
1412
We know the molecular weight of C8H7SO3Na
=12×8+1×7+32+16×3+23=206
we have to find, mole per gram of resin.
∴ 1g of C8H7SO3Na has number of mole
=weight of given resinMolecular weight of resin=1206mol
Now, reaction looks like,
2C8H7SO3Na+Ca2+→(C8H7SO3)2Ca+2Na
∵ 2 moles of C8H7SO3Na combines with 1 mol Ca2+
∵ 1 moles of C8H7SO3Na will combine with 12 mol Ca2+
∵1206 moles of C8H7SO3Na will combine with 12×1206 mol Ca2+=1412molCa2+