Q. No.Biochemical Oxygen Demand (BOD), is a measure of organic material present in water. BOD value less than 5 ppm indicates a water sample to be
1. Rich in dissolved oxygen
2. Poor in dissolved oxygen
3. Highly polluted
4. Not suitable for aquatic life
Which of the following statement(s) is wrong?
| 1. | Ozone is not responsible for the greenhouse effect. |
| 2. | Ozone can oxidize sulfur dioxide present in the atmosphere to sulfur trioxide. |
| 3. | Ozone hole is thinning of the ozone layer present in the stratosphere. |
| 4. | Ozone is produced in the upper stratosphere by the action of UV rays on oxygen. |
Sewage containing organic waste should not be disposed in water bodies because it causes major water pollution. Fishes in such a polluted water die because of
1. Large number of mosquitoes
2. Increase in the amount of dissolved oxygen
3. Decrease in the amount of dissolved oxygen in water
4. Clogging of gills by mud
Which of the following statements about photochemical smog is wrong?
| 1. | It has high concentration of oxidising agents |
| 2. | It has low concentration of oxidising agent |
| 3. | It can be controlled by controlling the release of NO2, hydrocarbons, ozone etc. |
| 4. | Plantation of some plants like pinus helps in controlling photochemical smog |
The gaseous envelope around the earth is known as atmosphere. The lowest layer of this is extended upto 10 km from sea level, this layer is
1. Stratosphere
2. Troposphere
3. Mesosphere
4. Hydrosphere
Dinitrogen and dioxygen are main constituents of air but these do not react with each other to form dioxides of nitrogen because ______.
| 1. | The reaction is endothermic and requires very high temperature |
| 2. | The reaction can be initiated only in presence of a catalyst |
| 3. | Oxides of nitrogen are unstable |
| 4. | N2 and O2 are unreactive |
The pollutants which come directly in the air from sources are called primary pollutants. Primary pollutants are sometimes converted into secondary pollutants. Which of the following belongs to secondary air pollutants?
1. CO
2. Hydrocarbon
3. Peroxyacetyl nitrate
4. NO
Which of the following statements is correct?
| 1. | Ozone hole is a hole formed in stratosphere from which ozone oozes out |
| 2. | Ozone hole is a hole formed in troposphere from which ozone oozes out |
| 3. | Ozone hole is thinning of ozone layer of stratosphere at some places |
| 4. | Ozone hole means vanishing of ozone layer around the earth completely |
The practice that does not come under green chemistry among the following is-
| 1. | Making use of soap made of vegetable oils instead of using synthetic detergents. |
| 2. | Using H2O2 for bleaching purposes instead of using chlorine-based bleaching agents. |
| 3. | Using bicycles for traveling small distances instead of using petrol/diesel based vehicles. |
| 4. | Using plastic cans for neatly storing substances. |
Which of the following conditions shows the polluted environment?
| a. | pH of rainwater is 5.9 |
| b. | Amount of carbon dioxide in the atmosphere is 0.03% |
| c. | Biochemical oxygen demand 10 ppm |
| d. | Eutrophication |
Choose the correct option
1. (a, b, c)
2. (b, c, d)
3. (c, d)
4. (a, b, d)
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