Note on Alcohol and its types.

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Alcohol.

Alcohols are hydroxyl derivative of alkanes containing –OH as a functional group. These compounds are obtained from alkanes replacing hydrogen atom by a hydroxyl group.

$$\underbrace{R-H}_{Alkane}\xrightarrow{-H\,,+OH}\underbrace{R-OH}_{Alcohol}$$

$$Where\,R\,is\,an\,alkyl\,group$$

In homologous series, alcohols are represented by molecular formula CnH2n+2.

Example of alcohol are as follows.

$$\underbrace{CH_3OH}_{Methanol}$$

$$\underbrace{C_2H_5OH}_{Ethanol}$$

$$\underbrace{C_3H_7OH}_{Propanol}$$

Classification of alcohols.

Alcohols are classified on the basis of

  1. On the basis of number of –OH group:-
  2. On the basis of nature of C-atoms containing –OH group.

1. On the basis of number of –OH group: On the basis , alcohols are classified as

  • Monohydric alcohol.
  • Dihydric alcohol.
  • Trihydric alcohol
  • Polyhydric alcohol.

Monohydric alcohol.

An alcohol heaving only one -OH group are called monohydric alcohol. Example.

$$\underbrace{CH_3OH}_{Methanol}$$

$$\underbrace{C_2H_5OH}_{Ethanol}$$

$$\underbrace{C_3H_7OH}_{Propanol}$$

Dihydric alcohol.

An alcohol containing two -OH group is called dihydric alcohol.

Image result for dihydric alcohol

Trihydric alcohol.

An alcohol containing 3-OH group are called Trihydric alcohol.

Image result for dihydric alcohol

Polyhydric alcohol.

Image result for Polyhydric alcohol.

2. On the basis of nature of C-atom containing monohydric alcohol are classified into three types.

  • Primary alcohol.
  • Secondary alcohol.
  • tertiary alcohol.

Primary alcohol. 10.

If carbon containing -OH group is bonded to non or one carbon atom,it is called primary alcohol or called 10.

$$\underbrace{CH_3OH}_{Methanol}$$

$$\underbrace{C_2H_5OH}_{Ethanol}$$

Image result for secondary alcohol

Secondary alcohol. 20

If the carbon containing -OH group is bonded with two C-atom it is called secondary alcohols.

Example

Image result for isobutyl alcohol structure

Tertiary alcohol.30.

If the carbon containing -OH group is bonded to two C atoms it is called tertiary alcohol.

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Important question.

Write a structural formula of secondary alcohol of C3H8O and give a method of its preparation using Grignard reagent.

The structural formula of secondary alcohol from the molecular formulaC3H8O is given below.

Image result for propan-2-ol

IUPAC name=Propan-2-ol

Reference.

Bahl, B S, Bahl, and Arun. Advanced Organic chemistry. S. Chand and company Ltd., n.d.

Sthapit, M K, R R Pradhananga, and K B Bajracharya. Foundations of chemistry. Taleju Prakashan, n.d.

Tewari, K S, S N Mehrotra, and N K Vishnoi. A textbook of organic chemistry. Vikash publishing House Pvt. ltd., n.d.

Verma, N K and S K Khanna. Compressive chemistry. 8th edition. Laxmi publications P. Ltd., 1999.

  1. Alcohols are hydroxyl derivative of alkanes containing –OH as a functional group.
  2. If carbon containing -OH group is bonded to non or one carbon atom,it is called primary alcohol or called 10.

  3. $$\underbrace{CH_3OH}_{Methanol}$$

  4. If the carbon containing -OH group is bonded to two C atoms it is called tertiary alcohol.
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