Carbon and its compounds 2

Question 1

What is soap?

Answer 1

Soaps are molecules of sodium or potassium salts of long chain carboxylic (fatty) acids, which show cleansing properties in water.

These fatty acids exist as glycerides(esters) in oil and fats which are obtained as a result of esterification reaction.

Fatty acids + glycerol-> glycerides (esters)

Question 2

Preparation of soap –

Answer 2

A glyceride can be converted into soap by reacting with either aq NaOH or KOH solution. This process is known as saponification.
- Thus soap is formed by ALKALI HYDROLYSIS of esters/glyceride

Question 3

Soap Micelle:

Answer 3

Soap molecules have a unique orientation in water. They form clusters of molecules in which the hydrophobic tail are in the interior surrounding the dirt particle and the ionic ends are on the surface. This formation is called a micelle.

Question 4

Detergents

Answer 4

They are ammonium or sulphonate salts of long chain carboxylic acids.

Question 5

Non renewable energy sources

Answer 5

These are energy sources which cannot be replaced easily when they get exhausted and also called conventional sources of energy.

e.g . Fossil fuels

Question 6

Fossil fuels

Answer 6

Fuels obtained from the dead remains of plants and animals which got buried millions of years ago.

Question 7

Formation of coal

Answer 7

It is formed from vegetable matter which got buried under the earth millions of years ago. Due to high temperature and pressure and in the absence of air inside the earth, this vegetable matter changed into coal, hence also called fossil fuels.

Question 8

Formation of petroleum

Answer 8

It is formed by decay of very small marine plants and animals buried under the earth about 400 million years ago. Due to excess of heat and pressure and in the absence of air it changes into oil called petroleum. Therefore it is a fossil fuel.

Question 9

Necessity of judicious use of coal and petroleum:

Answer 9

1. They are exhaustible and non-renewable sources of energy.
2. Their combustion pollutes air

· When combustion takes place, oxides of carbon, nitrogen and sulphur are formed.

· Carbon monoxide is formed instead of carbon dioxide if there is insufficient air.

· The oxides of sulphur, nitrogen and carbon monoxide are poisonous at high concentrations.

· Carbon dioxide is a green – house gas which leads to global warming.

Question 10

Contribution towards the conservation of fossil fuels

Answer 10

· Using fluorescent tubes

· Switching off unnecessary lights and electronic devices

· Using solar devices

· Prefer walking and cycling to using vehicles

· Getting the car properly maintained to improve fuel efficiency