QUESTION
Objective Question
If only ammonia was present in water, the only change in the given diagram would have been that the curve would
Answer
( Option D)
be passing through the origin A&B
Solution
In a standard breakpoint chlorination process, the very first section of the curve (portion AB) stays flat along the
bottom axis because the added chlorine is immediately destroyed by immediate reducing compounds like iron,
manganese, and nitrates. No residual chlorine can form during this initial phase.
If only ammonia is present in the water, these alternative reducing compounds are completely absent. As a result, the
added chlorine will instantly react with the ammonia to form chloramines from the very first drop. This shifts the starting
point of the residual curve directly back to the origin (Point A) rather than delaying it to Point B, causing the curve to pass
directly through the origin.
