Question

The upper limit of sodium intake for adults is 2300mg of sodium a day. Softened hard water can actually provide a significant amount of one's recommended daily allowance of sodium. Assuming hard water contains 200 ppm of calcium (5.00x10^-3 M). a. what mass of sodium would 2.0L of water contain after it is softened? (for every calcium ion removed by an exchange column, two sodium ions are released) b.What percentage of the UL for sodium would this water provide?

Answer 1

# From the given data in the problem, we can understand that

200 ppm of Ca ions = 400 ppm of Na

# 200 ppm of Ca =

# Similarly, 400 ppm of Na =

# If 200 mg of Ca is removed by coloumn chromatography then 400 mg of Na will also be removed during water treatment for one litre.

# Therefore, for two litre of water 800 mg of sodium will be removed.

# Softened hard water can actually provide a significant amount of one's recommended daily allowance of sodium. From this statement we can understand that 800 mg will be removed by treatment of water remaining amount of required sodium could be taken from this water .

i.e After Treatment

2L of water = 2300 mg - 800 mg of sodium

= 1500 mg of sodium

b) Percentage of the UL for Sodium from this water:

UL of sodium = 2300 mg per day

Amount of sodium from this water = 1500 mg

Therefore % of Na = (1500/2300) x 100

% of Na = 65.217