10th Class Chapter 3 Chemistry Long Questions

Homolocyclic compounds:

Organic compounds in which the ring is made up of only carbon atoms are called homocyclic compounds.These are further divided into two classes.

(Aromatic compounds) (Alicyclic compounds)

Aromatic compounds:

The organic compounds which contain at least one benzene ring in their molecule are called aromatic compounds.They are aromatic because of aroma or small they have:

They are also called benzenoid compounds.

Alicyclic Compounds:

The carbocyclic compounds which do not have benzene ring in their molecules are called alicyclic compounds.

CH2 CH2 CH2

CH2 CH2

CH2 CH2 cyclobutane

Cyclopropane

CH2 CH2

CH2 CH2 CH2 CH2

CH2 CH2 CH2 CH2

CH2

Coal:

The strong heating of coal in the absence of air is calle destructive distillation.

Types of products:

Four types of products are following:

Coal gas:

It is a mixture of H2,CH2 and CO which are burning gases.It produces heat on burning in air it is mainly used as a fuel in industry.

Ammonical Liquor:

It is a solution of ammonia gas in water it is used to prepare nitrogenous fertilizers.It is treated with sulphuric acid to produce ammonium sulphate fertilizers.

Coal tar:

It is thick black liquid, it is a mixture of more than 200 aromatic compound. They are separated by fractional distilliation.the black residue of coal tar is called pitch. It is used for surfacing of roads and roofs.

Coke:

It contains 98% carbon it is mainly used as a reducing agent in the extraction of metals especially iron. It is also used as fuel.

Litmus test:

Take 1cm3 of equeous solution or suspension or organic compound in a test tube add a few drops of blue litmus solution in it.A red colouration indicates the presence of carboxyle group- COOH or phenolic OH- group.

NAHCO3 solution test:

Take about 2cm3 of saturated equeous solution of NAHCO3 in a test tube.Add a oinch of given solid compound or few drops of given organic compound in it.Effervescene, due to evolution of CO indicates the presence of carboxyl group-COOH.

Fractional distillation:

Separation of fraction or components depending upon their boiling point ranges.

Petroleum:

Petroleum is a dark brownish or greenish black coloured viscous liquid. It is a complex mixture of several solid , liquid or gaseous hydrocarbons in water mixed with salts and earth particles.Petroleum is a main source of organic compounds.It consists of several compounds mainly hydrocarbons.These compounds are seperated by fractional distillation.These fractions and their uses are provided.Each fraction is not a single compound , rather each of it consists of different organic compounds.

Fractional distillation:

Seperation of fraction or components depending upon their boiling point ranges.

Petroleum:

Petroleum is a dark brownish or greenish black coloured viscous liquid. It is a complex mixture of several solid , liquid or gaseous hydrocarbons in water mixed with salts and earth particles.Petroleum is a main source of organic compounds.It consists of several compounds mainly hydrocarbons.These compounds are seperated by fractional distillation.These fractions and their uses are provided.Each fraction is not a single compound , rather each of it consists of different organic compounds.

Functional Group:

An atom or group of atoms or a double or triple bond whose presence give characteristic properties to an organic compound is called functional group.

It is the reactive part of the molecule.Each function group has its own characteristic reactions. Usually,the remainder the molecule is not involved in most of the reactions of the molecule.Organic

Compounds are classified into families on the basis of functional groups present in their molecules.

Example:

The hydroxyle group –OH is the functional group of alcohols and carboxyl group,-COOH I the functional group of carboxylic acids.

CH3-CH-OH

Ethylaleohol

O

II

CH3-C-OH

Acetic acid

In 1809, Swedish chemist J. Berzelius gave the concept of vital force of theory .Organic compounds are only formed in living organisms and it is impossible to prepare them in laboratories because they required the presence of a mysterious force i.e vital force which exists only in living organisms .

The branch of chemistry which deals with the study of hydrocarbons and their derivatives is called organic chemistry.

Organic compound:

Compound of carbon and hydrogen and their derivatives containing covalently carbon as an essential constituent are called organic compounds.

A formula which shows the actual number of atoms of each element in one molecular formula molecular formula of butane is C4H10.

A formula that shows the exact arrangement of atoms of different elements in a molecule of a compound is called a structural formula.

In aldehydes R-C-H, the carbonyl group is bonded to at least one hydrogen atom and so it occurs at the end of a carbon chain 2n ketnoes ,R-C-R carbon group –C-C is bonded to two carbon atoms and so it occurs with in a carbon chain.

It is used as fuel in homes as well as in industries it used as fuel in auto mobiles as compressed natural gas (CNG) it is used to make carbon black and fertilizers.

The food we eat daily such as milk eggs,meat, etc,carbon carbohydrates ,proteins, fats, vitamins etc are call organic compounds.

N- propyl is formed by the removed of the terminal H atom from either end of propane Ispropyl radical is formed by the removal of central H from propane.

Petroleum is a dark boownish or greenish black coloured viscous liquid it a complex mixture of gaseous hydrocarbons in water mixed salts and earth particles.

The gases which are found in coal gas are hydrogen methane carbon monoxide.

The strong heating of coal in the absence of air is called destructive ditillation.

The group of atoms obtained by the removal of one hydrogen atoms from an alkane is called an alkyl radical they are formed by the removing of one of the hydrogen atom of an alkane and are represented by a letter R, their name is written by replacing one by yl.

The functional group of either is –O-their general formula is R-O-R where R and R are alkyl groups.

Natural gas is a naturally occurring mixture or premixed combustion natural gas is a combustable mixture of hydrocarbon gases.

Different types of coal are as following :

Peat, Lignite, Bituminous Anthracite

Coke is 98% carbon it is left behind residue of coal:

Uses of coke:

It is mainly used as reducing agent in the extraction of metals especially iron it is also used as fuel.

The compounds which have some molecular formula but different arrangement of atoms

In their molecule or different structure formula are called isomers and this phenomenon is called isomerism :

Example: C4H12 have two

H3C-CH-CH3

I so butane

The formula which shows the sharing of electrons between various atoms in one molecule of the organic compound is called dot and cross formula.

The self linking property of carbon atoms through coralent bonds to form long straight or branched chains and rings of different size is called catenation.

Alkynes are hydrocarbons which are organic chemical compounds containing carbon (C) and hydrogen (H) atoms and the feature that make them recognized as alkynes is the presence of triple bonds.

Example; CH= CH ( ethyne)

Hydrocarbons containing one carbon to carbon double bond in their molecules are called alkanes.

Example: H2C = CH2 (Ethene)

A shortened or abbreviated structural formula is called a condensed structural formula.

Amphoteric compound is one that can react with both acids and bases Al2,O3 is an example of an amphoteric oxide.

Open chain compounds:

Open chain compounds are those in which the end carbon atoms are not joined with each other.

Example -C-C-C-C-

Closed chain compounds:

Closed chain are those in which the carbon atoms at the end of the chain are not free.

Example: CH2___CH2___CH2____CH2____CH2_____CH2