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Tuesday, January 28, 2020

Which are the compounds gives positive Tollen's test?

More general Tollen's test use for distinguishing between aldehyde and ketones here aldehyde gives positive Tollen's test while ketones gives negative Tollen's test.
But also 
Aldehyde, 
Alpha hydroxy ketone ,
Terminal alkyne, 
Halides ions, 
Alkyl hydroxy amines , 
Formic acid(only acid gives Tollen's test) Chatechol (Benzene1,2-diol),  
Hemiacetal,
Aromatic aldehyde such as Benzaldehyde  give positive Tollen's test.

Related Questions:
Both glucose and fructose are reducing sugars but sucrose is non-reducing in nature. Why?
Fructose contains a keto group, yet it reduces Fehling solution and Tollen's reagent. Why ?
What is Dunstan's test , How can it use for test Glycerol ?
What is luca's reagent and where is luca's reagent uses ?
What is Victory-Meyer's test and how can distinction between 1°, 2° and 3° alcohols by this ?
Benzaldehyde gives a positive test with Tollen's reagent but not with Benedict's and Fehling's solution. Comment why?
Aromatic amines are lesser basic than aliphatic amines.why ?
Which are the compounds gives positive Tollen's test?
What is Tollen's reagent?
What is Carbylamine test or Isocyanide test ?
What is Hinsberg's reagent and where Hinsberg's test use?
N-Ethyl-N-methyl propanamine does not show optical activity why?




What is Tollen's reagent?


Tollen's reagent is a mixture of liquid ammonia and silver nitrate , It was named after its discoverer, the German chemist Berhard Tollens. 

Basically positive test means Tollens' reagent oxidize, aldehyde aromatic aldehyde and alpha-hydroxy ketone functional groups into corresponding acid and  the precipitation of elemental silver, often producing a characteristic "silver mirror" on the inner surface of the reaction vessel.

                                        AgNO3 + NH4OH --> NH4NO3 +AgOH
Related Questions:

Both glucose and fructose are reducing sugars but sucrose is non-reducing in nature. Why?
Fructose contains a keto group, yet it reduces Fehling solution and Tollen's reagent. Why ?
What is Dunstan's test , How can it use for test Glycerol ?
What is luca's reagent and where is luca's reagent uses ?
What is Victory-Meyer's test and how can distinction between 1°, 2° and 3° alcohols by this ?
Benzaldehyde gives a positive test with Tollen's reagent but not with Benedict's and Fehling's solution. Comment why?
Aromatic amines are lesser basic than aliphatic amines.why ?
Which are the compounds gives positive Tollen's test?
What is Tollen's reagent?
What is Carbylamine test or Isocyanide test ?
What is Hinsberg's reagent and where Hinsberg's test use?
N-Ethyl-N-methyl propanamine does not show optical activity why?

Why do only methyl ketones gives positive haloform reactions?

The Haloform reaction given by only methyl ketones because it can form enolate ions by removal of alpha hydrogen and which is stabilised by de localisation of electron with carbonyl carbon therefore the alpha carbon can be bonded with three halogens atoms .

Which alcohol does not give iodoform test?

Ethanol and other terminal 2°alcohol  like Iso propyl alcohol , butan-2-ol, Petan-2-ol etc gives Iodoform test positive  other alcohol does not give Iodoform form reactions .

Why does ethanol cause Haloform (Iodoform) reactions?

Ethanol gives Iodoform test  positive because, under  the reaction conditions it oxidised to ethanal (acetaldehyde)  which is the only aldehyde that undergoes Haloform reaction.