B.O.D is connected with

(1) Organic matter

(2) Microbes

(3) Both

(4) None

Acid rain is due to an increase in the atmospheric concentration of : 

1. Ozone, and dust

2. $C{O}_{\mathrm{2,}}$ and CO

3. $S{O}_{\mathrm{3,}}$ and CO

4 $S{O}_{\mathrm{2,}}$ and $N{O}_2$

Soil erosion is greater when

(1) No rain occurs

(2) Winds do not blow

(3) The rainfall is evenly distributed

(4) The Rainfall is received in heavy down pour

Soil erosion can be prevented by : 

1. Overgrazing

2. Removal of vegetation

3. Afforestation (Plantation)

4. Increasing bird population

Soil conservation is the process where

1. Soil is aerated

2. Soil erosion is allowed

3. Soil is protected against loss

4. Sterile soil is converted into fertile soil

The Lassaigne's extract is boiled with conc. $HN{O}_3$  while testing for the halogens. By doing so, it:

1. decomposes $N{a}_{2}S$ and NaCN, if formed.

2. helps in the precipitation of AgCl.

3. increases the solubility product of AgCl.

4. increases the concentration of $N{O}_3^{-}$ ions.

Ether and benzene can be separated by :-

(1) Filtration

(2) Distillation

(3) Crystallization

(4) Sublimation

Which one of the following statements regarding photochemical smog is not correct?

(1) Photochemical smog is formed through a photochemical reaction involving solar energy

(2) Photochemical smog does not cause irritation in eyes and throat.

(3) Carbon monoxide does not play any role in photochemical smog formation

(4) Photochemical smog is an oxidizing agent in character

... is not a greenhouse gas :-
1. Hydrogen
2. Carbon dioxide
3. Methane
4. Nitrous oxide or $N_{2}O$

Which one of the following is not a common component of Photochemical Smog?

(1) Ozone

(2) Acrolein

(3) Peroxyacetyl

(4) Chlorofluorocarbons