113. Pick up the correct statement from the following :
A. pH value indicates acidity and alkalinity of sewage
B. In acidic sewage, the pH value is less than 7
C. In alkaline sewage, the pH value is more than 7
D. All the above.
114. The pH value of sewage is determined with the help of
A. Imhoff Cone
B. turbidimeter
C. potentiometer
D. none of these.
115. In sewage having fully oxidised organic matter, the nitrogen exists in the form of
A. nitrites
B. nitrates
C. free ammonia
D. aluminoid nitrogen
116. In very first stage of decomposition of the organic matter in sewage
A. nitrites are formed
B. nitrates are formed
C. carbondioxide is formed
D. ammonia is formed.
117. The presence of free ammonia in sewage, is detected by
A.( a) boiling
B. adding pottassium permanganate
C. adding sulphuric acid
D. phenol-di-sulphuric acid.
118. For detecting the nitrites in the sewage, the matching colour may be developed by adding
A. Pottassium permanganate
B. Sulphuric acid and napthamine
C. Phenol-di-sulphuric acid pottassium hydroxide
D. None of these.
119. For detecting the nitrates in sewage, the colour may be developed by adding
A. Pottassium permanganate
B. Sulphuric acid and napthamine
C. Phenol-di-sulphuric acid and pottassium hydroxide
D. None of these.
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