Ch. 9. Amazing world of carbon compounds
Q1. Fill in the blanks.
1. The organic compounds having double or triple bond in them are termed as _______(unsaturated)
2. The general formula of alkanes is _____________.
3. _____________ are known as parent organic compounds. (hydrocarbons)
4. Covalent compounds are generally soluble in ____________ solvents. (organic)
5. Triple bond can be obtained by sharing ____________ pairs or ________ electrons. (three, shared)
6. Hydrocarbons necessarily contain _____________ and ______________. (hydrogen, carbon)
Q2. Give the IUPAC name of the following compounds.
Q3. Write short notes on
i. The remarkable property of carbon atom to form bonds with itself and give rise to a single structure of chain is called catenation.
ii. Such carbon chains can be straight or branched forming large molecules.
iii. The two ends of some chains join together to form closed ring – like structures.
iv. While catenating, the bonds between carbon atoms can be single, double or triple covalent bonds.
2. Functional group
i. The atoms or group of atoms present in the molecule which determines characteristic property of organic compounds are called the functional group.
ii. Halides (F, Cl, Br, I) aldehyde (- CHO), Hydroxyl ( - OH), Carboxyl (- COOH), etc., are some of the functional groups.
iii. The chemical properties of different compounds having the same functional groups are different.
iv. There exists a homologous series of one particular type of functional group, e.g., alcohols, aldehydes, ketones, ethers, etc.
3. Homologous series.
i. A group of organic compounds containing same functional group which can be represented by the same general formula and which have similar trends in their properties are called a homologous series.
ii. In the general formula of compounds of a homologous series, the symbol R is used to represent its functional group.
iii. Alcohols (R – OH), Aldehydes (R – CHO), Carboxylic acid (R – COOH), Ketones(R-C(=O)-R') are some of homologous series and their general formulae.
iv. The alkanes family is a homologous family which have linear molecules. Examples: Ethane C2H6, Propane C3H8, Butane C4H10, Pentane C5H12.
Q4. Differentiate between: Detergents and soaps
i. Detergents are generally ammonium or sulphonate salts of long chain carboxylic acids.
ii. Detergents have a strong cleansing action.
iii. Oils or fats are not used in their manufacture, usually petrochemicals are used to produce detergents.
iv. They function well in hard or soft water.
i. Soaps are sodium or potassium salts of long chain carboxylic acids.
ii. Soaps have relatively weak cleansing action.
iii. Vegetable oils or animal fats are used along with hydroxide of sodium or potassium to manufacture soaps.
iv. They do not work well in had water but work well in soft water.
Q5. Answer the following.
1. Draw chain and ring structures of organic compound having six carbon atoms in them.
Ans. a) chain structure –
b) Ring structure: -
2. Which organic compounds are named as Alkanol in IUPAC system?
Ans. In IUPAC method, alcohols are named as AlKanol. In naming the alcholols by IUPAC method the last ‘e’ of the parent alkane is replaced by ‘ol’ to indicate the presence of OH group.
3. Explain: What do you understand by substitution reaction?
i. Reaction where substitution of one or more atoms in a molecule for another atom takes place are called substitution reactions. Saturated hydrocarbons undergo substitution reaction.
ii. In Substitution reaction one or more hydrogen atom of a hydrocarbon are replaced by some other atom (like chlorine)
iii. Ex: Substitution reaction of methane with chlorine.
Methane reacts with chlorine in the presence of sunlight to form methyl chloride and hydrogen chloride.
4. Which organic compounds readily undergo addition reactions? Why?
Ans. Unsaturated hydrocarbons undergo addition reactions, that is addition reactions are given by all the alkenes and alkynes. This is because reactants add to the carbon atoms of
double and bond to form a single product of saturated hydrocarbon.
5. State two examples of (organic) compound having covalent bond and two examples having ionic bond.
i. Hydrocarbons like methane and ethane have covalent bonds.
ii. In organic compounds line NaCl and KMnO4 have ionic bonds.
6. State and explain how alkanes are further classified.
Ans. Alkanes are saturated hydrocarbons with single bonds. Alkanes are further classified as:
i. Straight chain alkanes: The alkanes in which all the carbon atoms are attached by covalent bonds in a continuous chain are called straight chain alkanes or normal alkanes Eg. CH3 – CH2 – CH2 – CH3 is normal butane or n – butane.
ii. Branched chain alkanes: - The alkanes in which all the carbon atoms are not in a continuous chain and some of them are linked to other carbon atoms to make the branch are called branched chain alkanes.
a. The alkanes, in which there is only one carbon chain attached to the second carbon atom of the long chain are called iso – alkanes Eg.
b. The alkanes, in which there are two single carbon branches, attached the second carbon atom of the long chain are called neo – alkanes. Eg.
7. What are alkynes? Name the first member of alkyne family.
Ans. Hydrocarbons containing triple bonds between carbon atoms are alkynes. The first member of alkyne family is ethyne or acetylene
A wonderful image released by Michael Ströck under the GNU Free Documentation License: The structures of eight allotropes of carbon:a) Diamond b) Graphite c) Lonsdaleite d) C60 (Buckminsterfullerene) e) C540 Fullerene f) C70 Fullerene g) Amorphous carbon h) Single-walled carbon nanotube