Question

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): Chlorides should be absent in drinking water.
Reason (R): Chlorides give salty taste to water.
In the light of the above statements, choose the most appropriate answer from the options given below:

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A)
• B. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
• C. (A) is correct but (R) is not correct
• D. (A) is not correct but (R) is correct

Hint:

"Absent" is a very strong word in environmental engineering. Very few things (like E.coli) must be completely absent. Most parameters just have a maximum allowable limit.

Answer 1

The Correct Option is D

Concept: Drinking water standards (like IS 10500) provide acceptable limits for various ions. Absence is not required; rather, concentration management is the goal.

Step 1: Evaluate the Assertion (A).
Chlorides are naturally present in most water sources. According to Indian Standards (IS 10500), the acceptable limit for chloride is $250 \text{ mg/L}$, with a permissible limit of $1000 \text{ mg/L}$ in the absence of an alternate source. Therefore, saying chlorides "should be absent" is factually incorrect. Assertion (A) is false.

Step 2: Evaluate the Reason (R).
High concentrations of chloride ions, particularly when combined with sodium (as NaCl), impart a noticeable salty taste to the water. This is why the limit is set primarily for palatability. Thus, Reason (R) is correct.

Step 3: Conclusion.
Since (A) is incorrect and (R) is correct, option (4) is the appropriate choice.