Match the following and choose the correct option given below:-

Compound / Type	Use
A. Dry ice	I. Anti-knocking compound
B. Semiconductor	II. Electronic diode or triode
C. Solder	III. Joining circuits
D. TEL	IV. Refrigerant for preserving food

• A - I; B - II; C - IV; D - III

• A - II; B - III; C - I ; D - IV

• A - IV; B - III; C - II; D - I

• A - IV; B - II; C - III; D - I

An odd electron molecule among the following is

• CO

• SO₂

• CO₂

• NO

Green chemistry deals with

• study of plant physiology

• study of extraction of natural products from plants

• detailed study of reactions involved in the synthesis of chlorophyll

• utilization of existing knowledge base for reducing the chemical hazards along with developmental activities

A sample of sea water contains 5 × 10^-3 g of dissolved oxygen in 1 kg of the sample. The concentration of O₂ in that sea water sample in ppm is

• 5

• 5 × 10^-3

• 5 × 10^-2

• 5 × 10^-1

The gas emitted by supersonic jet planes that slowly depletes the concentration of ozone layer is

• CO

• NO

• SO₂

• O₂

The photochemical smog can be suppressed by

• nitrogen oxides

• hydrocarbons

• radical traps

• formaldehyde

Which among the following statements are correct?

(i) Carbon monoxide is neutral whereas SO₃ is acidic.

(ii) Potassium oxide is basic whereas nitrous oxide is acidic.

(iii) Aluminium and zinc oxides are amphoteric.

(iv) Sulphur trioxide is acidic whereas phosphorus pentoxide is basic.

(v) Carbon dioxide is netural whereas sulphur dioxide is amphoteric.

• (ii) and (iii)

• (i) and (iv)

• (i) and (iii)

• (ii) and (iv)

18.

Pick up the correct statement :

• CO which is major pollutant resulting from the combustion of fuels in automobiles plays a major role in photochemical smog

• Classical smog has an oxidizing character while the photochemical smog is reducing in character

• Photochemical smog occurs in day time whereas the classical smog occurs in early morning hours

• During formation of smog the level of ozone in the atmosphere goes down

In Antarctica ozone depletion is due to the formation of following compound :

• acrolein

• peroxyacetyl nitrate

• chlorine nitrate

• formaldehyde

Which one of the following is mainly responsible for depletion of ozone layer?

• Methane

• Cabon dioxide

• Water

• Chloro-fluoro carbons