2 The following test results were obtained for a treated was

2. The following test results were obtained for a treated wastewater effluent sample Concentration, mg/L Concentration, mg/L 260.0 64.0 440.4 35.1 30.0 Anion HCO Cation Ca2+ Mg Na 190.2 84.1 75.2 Cl NOj CO Fe2+ 0.2 Assignment #1 Page l a) Check the accuracy of the analytical measurements. (Refer to c page 69 o textbook). b) Determine the mole fraction of Ca2 and HCO. (Refer to cxample 2-1 page 68 of the textbook).

Solution

a)

both +ve and -ve molar equivalents are almost equal hence analytical measurement is of good accuracy.

b)

total moles= sum of molar mass of all ions

Ca3+ fraction = mole of Ca+2/total moles

thanks

,+ve ions	concentration	molar mass	valency	mole equ
Ca2+	190	40	2	9.500
Mg2+	84.1	24	2	7.008
Na+	75.2	23	1	3.270
K+	5.1	39	1	0.131
Fe2+	0.2	56	2	0.007
		Total=	19.916
,-ve ions	concentration	molar mass	valency	mole equ
HCO3-	260	61	1	4.262
SO4-2	64	96	2	1.333
Cl-	440.4	35	1	12.583
No3-	35.1	62	1	0.566
CO3-2	30	60	2	1.000
		Total =	19.745