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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)`
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Solution
The general molecular formula for the homologous series of alkynes is `underline("C"_"n""H"_("2n" - 2))`.
RELATED QUESTIONS
State any four characteristics of a homologous series
What is meant by homologous series of carbon compounds?
Succeeding members of a homologous series differ by ______.
What is homologous series ?
What is the difference in the molecular formula of any two adjacent homologues in terms of molecular mass?
Study the different conclusions drawn by students of a class on the basis of observations of preserved/available specimens of plants and animals.
I. Potato and sweet potato are analogous organs in plants.
II. Wings of insects and wings of birds are homologous organs in animals.
III. Wings of insects and wings of bats are analogous organs in animals.
IV. Thorns of citrus and tendrils of cucurbita are analogous organs in plants.
The correct conclusions are:
(A) I, and II
(B) II and IV
(C) I and III
(D) III and IV
Copy and complete the following table, which relates to the three homologous series of hydrocarbons:
| General formula | CnH2n | CnH2n-2 | CnH2n+2 |
| IUPAC name of the homologus series | |||
| Characteristic bond type | Single bonds | ||
| IUPAC name of the first member of the series | |||
| Type of reaction with chlorine | Addition |
What is a homologous series?
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.
The general formula of Alkane is _________________
Two statements are given - one labeled Assertion (A) and the other labeled Reason (R).
Assertion (A): In a homologous series of alcohols, the formula for the second member is C2H5OH and the third member is C3H7OH.
Reason (R): The difference between the molecular masses of the two consecutive members of a homologous series is 144.
As one ascends in any homologous series, physical properties change gradually.
There are different general molecular formula for all members of the 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 |
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’.
Consider the following molecular formulae of carbon compounds:
(i) CH3COOH (ii) CH3OH (iii) C2H6 (iv) C3H4 (v) C4H8
- Which one of these compounds belongs to homologous series of alcohols?
- Identify the compound having triple bond between carbon-carbon atoms.
- Write the molecular formula of the first member of the homologous series to which CH3COOH belongs.
- Write the general formula of the series to which the compound C4H8 belongs.
Consider the carbon compounds having following molecular formula:
(i) C3H6 (ii) C3H8 (iii) C4H6 (iv) C6H6 (v) C6H12
- State the number of double covalent bonds present in C3H8.
- Write the formula of first member of the homologous series to which the carbon compound C4H6 belongs.
- Which one of the above compounds forms a ring structure of carbon atoms?
- Identify, which of the above compounds, is a member of alkane series.
Name the following:
Group of organic compounds where the successive members follow a regular structural pattern, successive compounds differ by a 'CH2' group.
