Water Technology and Green Chemistry

Hardness of water sample: $y/V$ x Z x 100 x 1000 ppm $CaCO_3$ equivalent
V = volume fo water sample titrated

y = volume of disodium EDTA (burette reading)
Z = molarity of disodium EDTA solution

1 ml standard hard water contains 1 mg $CaCO_3$

Temporary hardness = total hardness – permanent hardness

Popular Atomic Weights

H -> 1
C -> 12

N -> 14
O -> 16
Na -> 23
Al -> 27

Cl -> 35.5

Ca -> 40
Cr -> 52

$\table Alkalinity,OH,C{O^{-2}_3},HC{O^{-2}_3};P = 0,0,0,M;P=1/2 M,0,2P,0;P=M,P,0,0;P<1/2M,0,2P,M-2P;P>1/2M,(2P-M),2(M-P),0$
P = Phenolphthalin akalinity
M = Methyl orange alkalinity = total alkalinity

$P=V_1/V$ x Z x 50 x 1000
$M = V_2/V$ x 50 x 1000

$V_1$ = Phenolphthalin end point

Z = Normality of acid
$V_2$ = Methyl Orange end point
V = Volume of water sample titrated

$Hardness = {\text"Amount of NaCl as " CaCO_3}/{\text"Litre of water"}$