chemistry

The requirement of water per capita per day, is

• 90 Ltrs

• 120 Ltrs

• 250 Ltrs

• 400 Ltrs

Both temporary and permanent hardness of water can be removed by

• boiling

• distillation

• filtration

• decantation

When temporary hard water is boiled, one of the substances formed is

• calcium bicarbonate

• calcium sulfate

• hydrogen chloride

• carbon dioxide

The purest form of naturally occurring water is

• rain water

• river water

• pond water

• well water

Sedimentation is a physical process used in wastewater treatment to

• remove particles that are less dense than water remove

• particles that are more dense than water remove the

• pertinacious material from the water none of the above

• none of the above

Which of the following physical method is used as germicidal in modern time for the treatment of drinking water?

• Chlorination

• Treating with potassium permangnate

• UV radiation

• Treating with bleaching powder

The common methods used for disinfection in waste water treatment plants are

• chlorination

• UV light

• both (a) and (b)

• Phenolic solvent

Permanent hardness of water is caused by the presence of

• bicarbonates of calcium and magnesium

• carbonates of sodium and potassium

• chlorides and sulfates of calcium and magnesium

• phosphates of sodium and potassium

Which of the following chemical is sometime added in the process of coagulation and flocculation?

• Aluminum sulphate

• Aluminum oxide’

• Calcium chloride

• None of these

Permanent hard water may be softened by passing it through

• sodium silicate

• sodium bicarbonate

• sodiumhexametaphosphate (Calgon)

• sodium phosphate