Question

Assertion : The diazotisation reaction must be carried in ice cold solution $(0-4 ^\circ C)$.
Reason :At higher temperature, benzenediazonium chloride reacts with water to give phenol.

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (A)

the conversion of $1^{\circ}$ aromatic amine into diazonium salt is known as diazotisation. The diazonium salt is only stable in cold, $0.5^{\circ} e$ or $273-278\, K$ temperature. and donot react with water
$C _{6} H _{5} NH _{2}+ NaNO _{2}+2 HCl \xrightarrow{0-5^{\circ} C} \underset{\text{(diazonium salt)}}{C _{6} H _{5} N _{2}^{+} Cl^{-}} + NaCl +2H _{2} O$
At higher temperature this salt reacts with water also.