An organic compound A of molecular formula C 6 H 6 O gives violet colour with neutral ferric chloride solution. Compound A when heated with zinc dust gives a hydrocarbon B . Also compound A reacts with phthalic anhydride and concentrated sulphuric acid to give compound C of molecular formula C 20 H 14 O 4 . Identify A , B and C . Explain the reactions.

(I) The compound which gives violet colour with neutral ferric chloride is phenol. So, the compound A is phenol C 6 H 5 OH . C 6 H 5 - OH A + FeCl 3 → H 3 Fe OC 6 H 5 6 Violet + 3 HCl (II) When phenol is treated with zinc dust, it gives a hydrocarbon that is benzene. C 6 H 5 - OH A + Zn → C 6 H 6 B + ZnO (III) When phenol reacts with phthalic anhydride and concentrated sulphuric acid, so it gives phenilphthalein C .

Write the chromogen, chromophore and auxochrome present in para hydroxy azo benzene.

The molecular formula of para hydroxy azo benzene is HO - C 6 H 4 - N ≡ N - C 6 H 5 . Therefore, Chromogen is diazo group - N = N - Chromophore is - N = N - - N = N - Auxochrome is hydroxy - OH .

Complete the reaction and write the name of the product. CH 3 CH 2 OH → 620 K Al 2 O 3 ?

The reaction involves dehydration of alcohols to alkenes. On passing the vapour of the alcohols over heated alumina catalyst at 620 K temperature, we will get alkene as a product during the process.Therefore, the following chemical reaction will take place when ethanol is pass over alumina to obtain ethene and water- CH 3 CH 2 OH Ethanol → 620 K Al 2 O 3 CH 2 = CH 2 Ethene + H 2 O

Identify to which type does the following complex reactions belongs to- dehydration of 2-methyl-2-butanol

It is the dehydration of secondary or tertiary alcohols by E1 reaction which involves formation of carbocation to form alkenes. It will be parallel and side chain reaction because of the formation of major and minor products. Therefore, the following reaction will take place when dehydration of 2-methyl-2-butanol occurs-

Give three methods of preparation of anisole.

The chemical formula of anisole is CH 3 OC 6 H 5 . The chemical name of anisole is methoxy benzene. It is an aromatic ether. The anisole can be prepared by the following methods. (I) Williamson synthesis- Methyl bromide is treated with sodium phenoxide to form anisole or methoxy benzene. This reaction is known as Williamson's synthesis reaction. C 6 H 5 - ONa Sodium pehnoxide + CH 3 - Br → CH 3 - O - C 6 H 5 Anisole + NaBr (II) Sodium phenoxide is treated with dimethyl sulfate to form anisole. 2 C 6 H 5 - ONa Sodium pehnoxide → - Na 2 SO 4 CH 3 O 2 SO 2 2 CH 3 - O - C 6 H 5 Anisole (III) Phenol is treated with diazomethane in the presence of Lewis acid to form anisole. C 6 H 5 - OH Phenol + CH 3 = N + = N - → BF 3 CH 3 - O - C 6 H 5 Anisole

E M B I B E

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR CHEMISTRY>Chapter -1 - Hydroxy Compounds and Ethers>Tamilnadu Board-2019>Q 12

MEDIUM

12th Tamil Nadu Board

IMPORTANT

Earn 100

How will you distinguish primary, secondary and tertiary alcohol by Lucas Test ?

Name: Classification of Alcohols, Phenols and Ethers
Uploaded: 2019-07-19
Duration: 5 min 33 s
Description: Alcohols, phenols, and ethers are classes of organic compounds that incorporate the C-O bond. Let’s watch the video and learn the classification of them.

Chapter-Wise 3D Chemistry Videos from Embibe Experts EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR CHEMISTRY

05 min 33 sec

Classification of Alcohols, Phenols and Ethers

Alcohols, phenols, and ethers are classes of organic compounds that incorporate the C-O bond. Let’s watch the video and learn the classification of them.

03 min 31 sec

Introduction to Alcohols, Phenols and Ethers

Let’s learn what alcohols, phenols, aryl alcohols and ethers are and the various types of alcohols based on their structure. Study the relationship between a...

Learn and Prepare for any exam you want !

|

|

|

|

|

|

|

|