MCQ
For fastest rate of reaction, $X_2$ must be


- ✓$F_2$
- B$Cl_2$
- C$Br_2$
- D$I_2$

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$\underset{(1)}{\mathop{C{{H}_{3}}C{{H}_{2}}CHO}}\,$
$\underset{(2)}{\mathop{\begin{matrix}
O \\
|| \\
C{{H}_{3}}-C-C{{H}_{3}} \\
\end{matrix}}}\,$
$\underset{(3)}{\mathop{C{{H}_{3}}-CH=CH-OH}}\,$

$C{H_4}(g) + 2{O_2}(g) \to C{O_2}(g) + 2{H_2}O(l)$ ;
${\Delta _r}{H_{300}} = - 212.7\ Kcal / mol$ .
The absolute value of ${\Delta _r}U_{300}^o$ for this reaction is .......$Kcal\,/\,mol$ $(R = 2\ cal/mol-K)$
$\begin{array}{*{20}{c}}
O \\
{||} \\
{{C_6}{H_5} - C - C{H_3}}
\end{array}\mathop {\xrightarrow{{(i)\,B{r_2}/KOH}}}\limits_{(ii)\,{H^ \oplus }} CHB{r_3} + [X]$
$[X]$ will be :