As per IS 10500 : 2012, identify the parameters whose maximum permissible limit is above 500 mg/L. (i) Total Hardness (ii) Total Alkalinity (iii) Chlorides (iv) Sulphate
- A(i) and (ii)
- B(i) and (iii)
- C(i), (ii) and (iii)Correct
- D(i), (ii), (iii) and (iv)
Solution
Concept
IS 10500 permissible limits comparison
Formula
NONE
Step-by-step solution
1. Check permissible limits under IS 10500:2012: 2. Total Hardness = 600 mg/L (> 500 mg/L). 3. Total Alkalinity = 600 mg/L (> 500 mg/L). 4. Chlorides = 1000 mg/L (> 500 mg/L). 5. Sulphates = 400 mg/L (< 500 mg/L). 6. Therefore, parameters (i), (ii), and (iii) have permissible limits above 500 mg/L. Answer: C
Explanation
According to IS 10500:2012, the maximum permissible limits in the absence of an alternate source are: Total Hardness = 600 mg/L, Total Alkalinity = 600 mg/L, Chlorides = 1000 mg/L, and Sulphates = 400 mg/L. Therefore, parameters (i), (ii), and (iii) have permissible limits above 500 mg/L, whereas Sulphate is limited to 400 mg/L.
Why the other options are wrong
A) Omits Chlorides which has a permissible limit of 1000 mg/L. B) Omits Total Alkalinity which has a permissible limit of 600 mg/L. D) Incorrectly includes Sulphates whose permissible limit is only 400 mg/L.
Shortcut
Sulphate permissible limit is only 400 mg/L; Hardness, Alkalinity (600), and Chloride (1000) exceed 500.
Common mistake
Assuming Sulphate permissible limit is 500 mg/L or above.
Correct answer: C) (i), (ii) and (iii)