Hydrocarbon and Its Compounds
Exact typing reconstruction from the supplied handwritten notes
Original Scanned PDF – View Notes
Lesson – 18.
Hydrocarbon and it’s Compounds.
Exercise.
2) Differences between.
(a) Saturated hydrocarbon and Unsaturated hydrocarbon
| Saturated hydrocarbon | Unsaturated hydrocarbon |
|---|---|
| The hydrocarbon having single covalent bond between the carbon atoms is called saturated hydrocarbon. | The hydro carbon having double or triple covalent bond between the carbon atoms is called unsaturated hydro carbon. |
| They are called paraffins. | They are called olefins. |
| Very stable and less reactive. | highly unstable and very reactive. |
(b) Alkane and Alkene
| Alkane | Alkene |
|---|---|
| The hydrocarbons having a single covalent bond between the carbon atoms are called alkane. | The hydrocarbon having double covalent bond between the carbon atoms are called alkene. |
| They are saturated hydrocarbons. | They are unsaturated hydrocarbons. |
| It’s general formula is CnH2n+2. | It’s general formula is CnH2n. |
(c) Monohydric alcohol and Dihydric alcohol
| Monohydric alcohol | Dihydric alcohol |
|---|---|
| alcohol which is formed by replacing one hydrogen atom with one OH atom of alkane is called monohydric alcohol. | alcohol which is formed by replacing two hydrogen atom with two OH atoms of alkane is called dihydric alcohol. |
| General formula is CnH2n+1OH. | General formula is CnH2n(OH)2. |
| Eg: Methyl alcohol, Ethyl alcohol. | Eg: Glycol. |
3) Give reason:
(a) Ethane is known as a saturated hydrocarbon.
Answer: Because, it have single covalent bonding between its carbon atoms.
(b) Glycerol is called a trihydric alcohol.
Answer: Because it is formed by replacing three hydrogen atoms with three (OH) atoms of alkane in chemical reaction.
4) Answer Questions.
(a) What are hydrocarbons? Write any four examples.
Answer: The carbonic compounds composed of only carbon and hydrogen atom called hydrocarbon. It’s four examples are:
- Methane.
- Ethane.
- Propane.
- Butane.
(b) What do you mean by a saturated hydrocarbon? Write with example.
Answer: The hydrocarbons having single covalent bond between the carbon atoms are called saturated hydrocarbon. Its example are; Methane, Ethane.
(c) Introduce methane gas along with its two uses.
Answer: Methane is a hydrocarbon with the chemical formula of CH4.
It’s uses are:
- It is used in the preparation of hydrogen gas.
- It is used for cooking.
(d) What is alcohol? Write its types on the basis of the hydroxyl group. Also write their examples along with their molecular formula and their structural formula.
Answer: The compounds formed by the replacement of one or more hydrogen atoms of alkanes by the (-OH) groups are alcohols.
It’s types are:
(e) Write the molecular formula, condensed formula and the structural formula of the following compounds.
| Name | Molecular Formula | CF | SF |
|---|---|---|---|
| Ethylene | C2H4 | H2C=CH2 | H2C=CH2 |
| Propene | C3H6 | H3C-CH=CH2 | CH3-CH=CH2 |
| Acetylene | C2H2 | HC≡CH | H-C≡C-H |
| Ethyl alcohol | C2H5OH | CH3CH2OH | CH3-CH2-OH |
| Glycerol | C3H5(OH)3 | CH2OH-CHOH-CH2OH | HO-CH2-CH(OH)-CH2-OH |
(f) Name the alcohol used for the following purposes.
(i) To make formaldehyde
→ Methanol.
(ii) Used in thermometer
→ Ethanol.
(iii) Used as an antiseptic
→ Ethanol.
(iv) To prepare alcoholic beverages
→ Ethanol.
(g) Write the structural formula of ethylene. What type of bond is found between its hydrogen and carbon? Why is the bond between its carbon atom weak?
There is single covalent bond between its hydrogen and carbon atom. The bond between the two carbon atom is double bond. Double bond is weak because it is more reactive and can easily break than a single bond during chemical reactions.
(h) Study the following structural formula of a hydrocarbon and answer the following questions.
(i) Write IUPAC name of this compound.
Answer: Methane Ethane.
(ii) Is it a saturated hydrocarbon? Write with reason.
Answer: Yes, it is a saturated hydrocarbon because its carbon atoms form single covalent bond.
(iii) Which compound will form if one of the hydrogen atom is replaced with a (-OH) group in the given compound?
Answer: Ethyl Alcohol will form.
(i) Write any three uses of methane gas.
Answer: Three uses of methane are:
- Used as fuel in industries.
- Used to prepare carbon black.
- Used in industries to prepare hydrogen gas.
(j) Write major uses of each of ethane and propane.
The major uses of ethane are:
- Used in metal welding.
- Used in the production of refrigerants and industrial chemicals.
- Production of ethylene, necessary for plastics and chemicals.
The major uses of propane are:
- Used as fuel for cooking and heating.
- Used to make different types of carbonic compounds.
- Used as coolant in petroleum industries.
(k) Define the following terms:
(i) Saturated hydrocarbon
Answer: Hydrocarbon having single covalent bond between its carbon atoms.
(ii) Unsaturated hydrocarbon
Answer: Hydrocarbon having double or triple covalent bonding between its carbon atom.
Alkane:
Saturated hydrocarbon having single covalent bond between carbon atoms.
Alkene:
Unsaturated hydrocarbon having double covalent bonding between carbon atoms.
Alkyne:
Unsaturated hydrocarbon having triple covalent bonding between carbon atoms.
Functional group:
An atom or group of atom responsible for the characteristic chemical reaction of a compound.
or
specific atom or group of atom in a molecule that determines its chemical properties and reactions.
Homologous series:
A series of organic compounds with the same functional group and similar chemical properties and structure where each member differing -CH2– from the next.
(l) Write the molecular formula of the following compounds.
Glycerol: C3H8O3
Methane: CH4
Ethanol: C2H5OH
Butane: C4H10
Propane: C3H8
Acetylene: C2H2
Ethene: C2H4
Ethane: C2H6
Propyne: C3H4
Methyl alcohol: CH3OH
(m) Write the name and structural formula of the alcohol used in spirit lamps.
Answer: The alcohol used in spirit lamp is called “ethanol” or “Ethyl Alcohol”.
(n) Name the compound formed by the replacement of three hydrogen atoms with three hydroxyl groups (-OH) from propane.
Also write its IUPAC name along with its structural formula. Write its three uses.
Answer: The compound formed by the replacement of three hydrogen atoms with three hydroxyl groups (-OH) from propane is called glycerol or glycerine.
IUPAC name: propane-1,2,3-triol
It’s three uses are:
- Used as sweetening agent in food.
- Used to make soap, lotion, cosmetics.
- Used to protect skin by trapping moisture and prevent its dryness.
Rama has a problem of dry skin in her hands, feet and face. Which compound can be used to solve her problem? Write the IUPAC name and the structural formula of that compound.
Answer: “Glycerol” or “glycerine” can be used to solve her problem. IUPAC name is propane-1,2,3-triol.
Its structural formula is:
Discussion
Share a helpful question, idea, or explanation with other students.