BOD and COD

Q. What is wilting? What are the causes of this condition? [2 MARKS]

Q. Eutrophication leads to a steep increase in BOD and causes a hypoxic condition in water bodies.

1. True
2. False

Q. Arrange the following options in ascending order of their BOD value:
(I) sample of highly polluted pond water (II) sample of unpolluted pond water (III) distilled water

1. III - I - II
2. II - III - I
3. III - II - I
4. I - III - II

Q.

What are the harmful effects of arsenic on human health?

1. Skin thickening and pigmentation

2. Cancer

3. Nervous system damage

4. Nausea

Q.

Dissolved oxygen is dependent on the BOD

Q.

How are biological oxygen demand and dissolved oxygen related?

1. Inversely

2. None of these

3. Not dependent on each other

4. Directly Proportional

Q.

Suji adulterated with iron filling causes

1. Tetanus

2. Paralysis

3. Death

4. Blindness

Q.

The amount of O₂ required by bacteria in water to breakdown wastes into simple inorganic substances is called

1. Eutrophication

2. Oxygen depletion

3. Biochemical oxygen demand (BOD)

4. Biological magnification

Q.

The amount of oxygen required by bacteria in water to break down wastes into simple inorganic substances is called ___

Q. State whether true or false:
Eutrophication literally means excessive nutrients.

1. True
2. False