Top 10 Viva/interview questions on Dissolved Oxygen Test

The term Dissolved Oxygen is used to describe the amount of oxygen dissolved in a unit volume of water. Dissolved oxygen (DO) is essential for the maintenance of healthy lakes and rivers. It is a measure of the ability of water to sustain aquatic life.

The dissolved oxygen content of water is influenced by the source, raw water temperature, treatment and chemical or biological processes taking place in the distribution system.

In a healthy body of water such as a lake, river, or stream, the dissolved oxygen is about 8 parts per million. The minimum DO level of 4 to 5 mg/L or ppm is desirable for survival of aquatic life.
Here are some questions on Dissolved Oxygen test in water sample

.

1. Winkler titration method is based on _____ property of Dissolved Oxygen.

a) Reduction
b) Oxidation
c) Redox
d) Decomposition

2. Dissolved oxygen in the water mainly depends upon Organic content of the water.

a) True
b) False

3. The ingredients of Alkali are NaOH, NaI

a) NaN4
b) NaN3
c) NaN2
d) NaN

4. The precipitate formed after the addition of MnSO4 and Alkali azide is _______.

a) Manganese Hydroxide
b) Sodium sulphate
c) Potassium sulphate
d) Manganese oxide

5. Dissolved Oxygen depends only on Physical Properties of the water.

a) True
b) False

6. Along the stream the increase in dissolved oxygen in water will be at the

a) riffles
b) warm pool
c) bank erosion
d) top

7. The dissolved Oxygen in potable water_______.

a) imparts freshness
b) improves taste
c) improves smell
d) imparts colour

8. Sulphide and Sulphur dioxide interfere in the determination of dissolved oxygen.

a) True
b) False

9. The sample obtained for testing Dissolved Oxygen can be preserved by

a) adding the reagents and stored at 10 to 20 for up to 8 hours
b) storing at room temperature for up to 24 hours
c) storing at 0 for up to 24 hours
d) adding the reagents and stored at room temperature for up to 24 hours

10. Minimum DO in the fresh water for the survival of aquatic life is

a) 0 mg/l
b) 2 mg/l
c) 8 mg/l
d) 4 mg/l

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