1
GATE CE 2012
MCQ (Single Correct Answer)
+2
-0.6
A water sample has a pH of 9.25. The concentration of hydroxyl ions in the water sample is
A
$$10^{-9.25}$$ moles/L
B
$$10^{-7.75}$$ moles/L
C
0.302 mg/L
D
3.020 mg/L
2
GATE CE 2010
MCQ (Single Correct Answer)
+2
-0.6
Ion concentrations obtained for a groundwater sample (having pH=8.1) are given below.
Ion $$Ca^{2+}$$ $$Mg^{2+}$$ $$Na^+$$ $$HCO_3^-$$ $$SO_4^{2-}$$ $$Cl^{-}$$
Ionconcentration(mg/L) 100 6 15 250 45 39
Atomic Weight Ca=40 Mg=24 Na=23 H=1,C=12,O=16 S=32,O=16 Cl=35.5

Total hardness (mg/L as $$CaCO_3$$) present in the above water sample is
A
205
B
250
C
275
D
308
3
GATE CE 2010
MCQ (Single Correct Answer)
+2
-0.6
Ion concentrations obtained for a groundwater sample (having pH=8.1) are given below.
Ion $$Ca^{2+}$$ $$Mg^{2+}$$ $$Na^+$$ $$HCO_3^-$$ $$SO_4^{2-}$$ $$Cl^{-}$$
Ionconcentration(mg/L) 100 6 15 250 45 39
Atomic Weight Ca=40 Mg=24 Na=23 H=1,C=12,O=16 S=32,O=16 Cl=35.5

Carbonate hardness (mg/L as $$CaCO_3$$) present in the above water sample is
A
205
B
250
C
275
D
289
4
GATE CE 2008
MCQ (Single Correct Answer)
+2
-0.6
A wastewater sample contains $$10^{-5.6}$$ mol/l of OH- ions at $$25^o$$ C. The pH of this sample is
A
8.6
B
8.4
C
5.6
D
5.4
GATE CE Subjects
Fluid Mechanics and Hydraulic Machines
EXAM MAP
Medical
NEET
Graduate Aptitude Test in Engineering
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CBSE
Class 12