In the Liebermann's nitroso reaction,the sequ | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(A) The Liebermann's nitroso reaction is a test for phenols. When phenol is treated with $NaNO_2$ and concentrated $H_2SO_4$,it forms a $p$-nitrosophe

Vedclass · Accepted Answer

Brown or red $	o$ green $	o$ deep blue

Vedclass · Answer

(A) The Liebermann's nitroso reaction is a test for phenols. When phenol is treated with $NaNO_2$ and concentrated $H_2SO_4$,it forms a $p$-nitrosophenol. This $p$-nitrosophenol reacts with excess phenol to form an indophenol dye. The colour changes observed during the reaction are: $1$. Initially,the solution turns red or brown. $2$. On heating or dilution,it turns green. $3$. Upon adding water or alkali,it turns deep blue. Therefore,the sequence is $Red/Brown 	o Green 	o Deep \ Blue$.

List-$I$	List-$II$
$a$. $(i)$ $NaOH$,$(ii)$ $CO_2$,$(iii)$ $H^{+}$	$i$. Benzoquinone
$b$. $(i)$ Aqueous $NaOH + CHCl_3$,$(ii)$ $H^{+}$	$ii$. Benzene
$c$. $Zn$ dust,$\Delta$	$iii$. Salicylaldehyde
$d$. $Na_2Cr_2O_7, H_2SO_4$	$iv$. Salicylic acid

List-$I$ (Compound)	List-$II$ ($pK_a$ value)
$A$. Ethanol	$I$. $10.0$
$B$. Phenol	$II$. $15.9$
$C$. $m$-Nitrophenol	$III$. $7.1$
$D$. $p$-Nitrophenol	$IV$. $8.3$

In the Liebermann's nitroso reaction,the sequential changes in the colour of phenol occur as:

Similar Questions

Consider the following reaction:
$Phenol$ $\xrightarrow{Zn\,dust} X$ $\xrightarrow[{Anhyd.\,AlCl_3}]{CH_3Cl} Y$ $\xrightarrow{Alkaline\,KMnO_4} Z$
The product $Z$ is:

Out of the two compounds shown below,the vapour pressure of $B$ at a particular temperature is expected to be:

The order of melting point of ortho-,meta-,and para-nitrophenol is

Match List-$I$ with List-$II$:

List-$I$ (Compound) List-$II$ ($pK_a$ value)

$A$. Ethanol $I$. $10.0$

$B$. Phenol $II$. $15.9$

$C$. $m$-Nitrophenol $III$. $7.1$

$D$. $p$-Nitrophenol $IV$. $8.3$

Choose the correct answer from the options given below:

Vedclass Test Series

Exam Paper Generator

Online Exam Module