Dissolved Oxygen - Viva

High amount of Dissolved Oxygen in a lake indicate --------

• Excessive aquatic plant or algae blooms

• Better water quality

• High turbidity

• Less water quality

If sample water does not contain enough microorganism then what needed to be done

• Seeding the sample

• Boiling the sample

• Treating it with alkaline solution

• All of the above

Why is the Concentrated Sulphuric acid added to the sample after precipitates settle down?

• To neutralize alkaline iodide-azide solution

• For dissolution of precipitate

• To prevent escape of iodide ions from solution for titration

• None of these

According to drinking water specification provided by IS 10500 (2012), what should be range of DO of drinking water

• Greater than 2mg/l

• Less than 1mg/l

• Greater than 1mg/l

• None of the above

The method used to measure Dissolved Oxygen in this experiment is----------

• Mohr's method

• EDTA method

• Winkler's method

• Titrimetric method

A minimum DO of A minimum DO of-------------- is desirable for the survival of aquatic life

• 4 to 5 mg/l

• 1 to 2 mg/l

• 2 to 3mg/l

• 5 to 6mg/l

Choose the reagents used for DO determination

• Manganese sulphate

• Alkali iodide azide

• None of the above

• All of the above

The titrant used for DO determination is

• Sodium thiosulphate

• Potassium thiosulphate

• Iodine Sulphate

• Sodium chloride

The indicator used for titration is------

The colour change is from ------- to colourless during the titration process of DO determination.