A. Hydrochloric acid
B. Lime
C. Copper sulphate
D. Sodium sulphate
A. Evaporation & chemical precipitation
B. Biological methods & adsorption in ion exchange materials
C. Fixing into a solid mass with cement and sinking deep in the sea
D. All A., B. & C.
A. Nitric acid making
B. Nitrogenous fertiliser
C. Detergent
D. Any of these
A. 5
B. 100
C. 1000
D. 2000
A. Sedimentation tank
B. Circular clarifier
C. Mechanical flocculation
D. Chemical coagulation
A. Ferrous sulphate
B. Alum
C. Lime
D. Hydrazine
A. 100
B. 1000
C. 400
D. 4000
A. Poor visibility due to sky darkening
B. Irritation in eyes
C. Respiratory trouble
D. All A., B. and C.
A. Forestation
B. Rain
C. Green house effect
D. Vegetation
A. 0.1 to 1
B. 3 to 6
C. 10 to 15
D. 15 to 20