232. Low turbidity of water is detected by
A. Turbidity tube
B. Jackson turbidity meter
C. Baylis turbidimeter
D. Hellipe turbidimeter

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233.  Maximum permissible colour for domestic water supplies, based on Cobalt scale, is
A. 5 P.P.M.
B. 10 P.P.M.
C. 15 P.P.M.
D. 20 P.P.M.

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234.  Maximum threshold number permitted for indicating the odour of public water supplies, is
A.1
B.2
C.3
D.4

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235. If pH value of water is
A. 7 water it is said to be neutral
B. less than 7 it is said to be acidic
C. more than 7 it is said to be alkaline
D. all the above.

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236.  For maximum alkalinity of water, pH value should be
A. zero
B. less than 7
C. more than 7
D.14

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237.  Disinfection of drinking water is done to remove
A. turbidity
B. odour
C. colour
D. bacterias

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238.  The main disadvantage of hard water, is
A. greater soap consumption
B. scaling of boilers
C. corrosion and incrustation of pipes
D. all the above.

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