Advertisements
Advertisements
Question
The general molecular formula for the homologous series of alkynes is _______.
Options
CnH2n
`"C"_"n""H"_("2n" + 2)`
`"C"_"n""H"_("2n" - 2)`
`"C"_"n""H"_("2n" - 1)`
Advertisements
Solution
The general molecular formula for the homologous series of alkynes is `underline("C"_"n""H"_("2n" - 2))`.
RELATED QUESTIONS
Write the next homologue of the following: C4H6
What is meant by homologous series of carbon compounds?
Write the molecular formula of two consecutive members of homologous series of aldehydes. State which part of these compounds determines their
- physical and
- chemical properties
The molecular formula of a homologue of butane is:
(a) C4H8
(b) C3H6
(c) C4H6
(d) C3H8
Give the dot diagram of the first member of the alcohol.
Give the structure of the second member of the alcohol group.
Why homologous series of carbon compounds are so called? Write chemical formula of two consecutive members of a homologous series and state the part of these compounds that determines their (i) physical properties, and (ii) chemical properties.
Write names of first four homologous series of alcohols.

Give three points to differentiate between saturated and unsaturated
hydrocarbons.
Haloalkanes react with alkalies to produce alcohol. Give the equation for the preparation of the second member of the homologous series of alcohol. State under what condition the reaction occurs.
As one ascends in any homologous series, physical properties change gradually.
Complete the following table for the homologous series of alkanes.
| Name | Molecular formula | Condensed structural formula | Number of carbon atom | Number of -CH2- units | Boiling point °C |
| Methane | CH4 | CH4 | 1 | 1 | -162 |
| Ethane | C2H6 | CH3–CH3 | 2 | 2 | -88.5 |
| Propane | C3H8 | CH3–CH2–CH3 | 3 | 3 | -42 |
| Butane | C4H10 | CH3–CH2–CH2–CH3 | ______ | ______ | 0 |
| Pentane | C5H12 | CH3–CH2–CH2–CH2–CH3 | ______ | ______ | 36 |
| Hexane | C6H14 | CH3–CH2–CH2–CH2–CH2–CH3 | ______ | ______ | 69 |
Complete the following table for homologous series of Alkenes.
| Name | Molecular formula | Condensed structural formula | Number of carbon atom | Number of -CH2- units | Boiling point °C |
| Ethene | C2H4 | CH2 = CH2 | 2 | 0 | -102 |
| Propene | C3H6 | CH3–CH = CH2 | 3 | 1 | -48 |
| 1-Butene | C4H8 | CH3–CH2–CH = CH2 | ______ | ______ | -6.5 |
| 1-Pentene | C5H10 | CH3–CH2–CH2–CH = CH2 | ______ | ______ | 30 |
Which of the following pairs can be the successive members of a homologous series?
Which of the following does not belong to the same homologous series?
A carbon compound ‘A’ having melting point 156K and boiling point 351K, with molecular formula C2H6O is soluble in water in all proportions.
- Identify ‘A’ and draw its electron dot structure.
- Give the molecular formulae of any two homologues of ‘A’.
Write the chemical formula of two consecutive homologous of organic compounds having functional group - OH.
What happens to the (i) boiling point and (ii) solubility of organic compounds of a homologous series as the molecular mass increases?
Name and draw the electron dot structure of first homologue of alkynes series.
