Download App

9. Hydricarbon — Chemistry STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 ScienceChemistry9. Hydricarbon1 Mark
MCQ
Alcoholic solution of $KOH$ is used for
  • A
    Dehydration
  • B
    Dehydrogenation
  • ✓
    Dehydrohalogenation
  • D
    Dehalogenation
✓

Answer

Correct option: C.
Dehydrohalogenation
c
(c) $C{H_3} - C{H_2} - Br + \mathop {KOH}\limits_{{\rm{alk}}}\,\,  \xrightarrow{Dehydrohal ogenation}  \,\,C{H_2} = C{H_2} + KBr + {H_2}O$

In alcoholic $KOH$ alkoxide ions $(R{O^ - })$ are present which is a strong base. They abstract proton from ?-carbon of alkyl halide and favours elimination reaction

$\mathop {ROH}\limits_{{\rm{Alcohol}}} + KOH \to \mathop {ROK + {H_2}O}\limits_{{\rm{Potassium \,alkoxide}}} $

$ROK \to \mathop {R{O^ - }}\limits_{{\rm{Alkoxide \,ion}}} + {K^ + }$

$R{O^ - } + H - \mathop {C{H_2}}\limits^\beta - \mathop {C{H_2}}\limits^\alpha - Br \to ROH + C{H_2} = C{H_2} + Br$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "M.C.Q (1 Marks)" from 9. Hydricarbon→9. Hydricarbon — all question types→Chemistry STD 11 Science question papers→Gujarat Board STD 11 Science question papers→Gujarat Board question paper generator→

Similar questions

In the reaction $Me -C \equiv C - Et \xrightarrow{{Na/liq.N{H_3}}}P\xrightarrow[{CC{l_4}}]{{B{r_2}}}(Q)$ ; then $Q$ is
→
Among the following gases which one is damaging the ozone layer?
→
Borax is actually made of two tetrahedra and two triangular units joined together and should be written as : $Na_2[B_4O_5(OH)_4]·8H_2O$

Consider the following statements about borax :

$a.$  Each boron atom has four $B-O$ bonds

$b.$  Each boron atom has three $B-O$ bonds

$c.$  Two boron atoms have four $B-O$ bonds while other two have three $B-O$ bonds

$d.$  Each boron atom has one $-OH$ groups

Select correct statement(s) :

→
The equilibrium concentrations of the species in the reaction $A + B \rightleftharpoons C + D$ are $2,3,10$ and $6\,mol\,L-1$, respectively at $300\,K . \Delta G ^{\circ}$ for the reaction is ( $\left.R =2\,cal / mol\, K \right)$
→
Which of the following has lowest knocking property
→
Among the following, total number of meta directing functional groups is__________ (Integer based)

$ -\mathrm{OCH}_3,-\mathrm{NO}_2,-\mathrm{CN},-\mathrm{CH}_3-\mathrm{NHCOCH}_3, $

$ -\mathrm{COR},-\mathrm{OH},-\mathrm{COOH},-\mathrm{Cl}$

→
The number of bonding pairs electron $\text{(X)}$ and lone pairs electron $\text{(Y)}$ around the central atom in the $\text{I}_3^-$ion are $\text{X} + \text{Y}$ :
→
Which of the following have identical bond order?
→
The dissociation constant of water is represented by $\text{K}=\frac{[\text{H}_3\text{O}^+][\text{OH}^-]}{[\text{H}_2\text{O}]}$$\text{or }=[\text{H}^+][\text{OH}^-]\text{K}_{\text{w}}$ is called:
→
The $IUPAC$ name of $\begin{matrix}
   HO-CH-COOH  \\
   |\,\,\,\,\,\,\,\,\,\,\,\,  \\
   HO-CH-COOH  \\
\end{matrix}$ is
→