Racemises of 1- Chloro -1- phenylethane

Question:  A solution of (−)−1 − chloro − 1− phenylethane in toluene racemises slowly in the presence of a small amount of SbCl₅, due to the formation of :

(1) carbanion

(2) carbene

(3) carbocation

(4) free radical

Answer:  According to question, (−)−1 − chloro − 1− phenylethane racemises in the presence of SbCl_5.

 It  racemises slowly due to formation of intermediate compound.

 This intermediate compound is a carbocation. Thus, option c is correct. 

Colour of Nitric acid

Question: Why does concentrated nitric acid trun yellow brown upon long standing?

Answer: Nitric acid (HNO₃) is colourless in pure form. But it tends to acquire yellow brown colour as it become older. This is because it is a highly strong mineral acid. Due to this, it decomposes easily into oxides of nitrogen (NO₂), oxygen and water.

The produced nitrogen oxides dissolve partly or completely in the acid and give yellow or even red colour at higher temperatures.