Civil Engineering - UPSC Civil Service Exam Questions - Discussion

Discussion Forum : UPSC Civil Service Exam Questions - Section 7 (Q.No. 42)
42.
A sample of ground water at a pH of 7.0 contains 122 mg/l of bicarbonates. What is the alkalinity of this water (in terms of CaC0 ) ?
120 mg/1
60 mg/1
100 mg/1
200 mg/l
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
3 comments Page 1 of 1.

MOHAMMAD RIZWAN said:   6 years ago
Alkalinity, in this case, can be calculated as,
amount of sample in mg/L * (Equivalent wt of CaCo3/Equivalent wt of ion).

Here,
Amount of Sample = 122mg/L.
Equivalent wt of CaCO3 = 50.
Equivalent wt of HCO3-- = 61.

Therefore : 122*(50/61)=100mg/L as CaCO3.

Also,
Eq wt can be calculated as,
Eq Wt= Molecular Wt/Valancy.
Eq wt of CaCO3 = 100/2.
Wq wt of HCO3- = 61/1.
Molecular wt of HCO3-= (1+12+(16*3)) = 61.
(3)

Mudassir said:   6 years ago
Equivalent of hco3 is 1.
So, 1*50 will be 50.

Vikram Syal said:   7 years ago
bicarbonate means hco3 negative, equivalent wt of HCO3 IS 2.

No of gram equivalent = given wt./equivalent wt of ca2co3 50.

Given wt.= 2*50 = 100.

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