Advertisements
Advertisements
Question
Give the names and the structural formula of the first three members of the homologous series of alkanes.
Advertisements
Solution
| Sr. No. | Members | Structural formula |
| 1. | Methane | \[\begin{array}{cc} \ce{H}\\ |\\ \ce{H - C - H}\\ |\\ \ce{H}\\ \end{array}\] |
| 2. | Ethane | \[\begin{array}{cc} \ce{H}\phantom{...}\ce{H}\\ |\phantom{....}|\\ \ce{H - C - C - H}\\ |\phantom{....}|\\ \ce{H}\phantom{...}\ce{H}\\ \end{array}\] |
| 3. | Propane | \[\begin{array}{cc} \ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\\ |\phantom{....}|\phantom{....}|\\ \ce{H - C - C - C - H}\\ |\phantom{....}|\phantom{....}|\\ \ce{H}\phantom{...}\ce{H}\phantom{...}\ce{H}\\ \end{array}\] |
APPEARS IN
RELATED QUESTIONS
Write the molecular formula of the 2nd and 3rd member of the homologous series where the first member is ethyne.
An organic compound having the molecular formula C3H6O can exist in the form of two isomers A and B having different functional groups. The isomer A is a liquid which is used as a solvent for nail polish. The isomer B is also a liquid. An aqueous solution of one of the lower homologues of B is used for preserving biological specimens in the laboratory
(a) What is compound A?
(b) Write the electron-dot structure of A.
(c) What is compound B?
(d) Write the electron-dot structure of B.
(e) Name the lower homologue of compound B which is used in preserving biological specimens.
What is homologous series ?
What is a homologous series?
What is the difference in the molecular formula of any two adjacent homologues:
(i) In terms of molecular mass
(ii) In terms of number and kind of atoms per molecule?
Cyclohexane : Cyclic hydrocarbon : : Isobutylene : _______
Write a short note.
Homologous series
Complete the following table for homologous series of alcohols.
| Name | Molecular formula | Condensed structural formula | Number of carbon atom | Number of -CH2- units | Boiling point °C |
| Methanol | CH4O | CH3-OH | 1 | 1 | 63 |
| Ethanol | C2H6O | CH3–CH2-OH | 2 | 2 | 78 |
| Propanol | C3H8O | CH3–CH2–CH2-OH | ______ | ______ | 97 |
| Butanol | C4H10O | CH3–CH2–CH2–CH2–OH | ______ | ______ | 118 |
Which of the following does not belong to the same homologous series?
Consider the carbon compounds having following molecular formula:
(i) C2H2 (ii) C2H5 (iii) C3H7OH (iv) C2H6COOH (v) CH3CHO
- Identify which one of the above compounds, is a member of aldehyde series.
- Write the general formula of the series to which compound C2H2 belongs.
- Which one of the above compounds has triple bonds between carbon-carbon atoms?
- Write the molecular formula of the first member of the homologous series to which the compound C3H7OH belongs.
