Arrange the following carbanions in the decreasing order of stability:
I. $p$-$\mathrm{Br{-}C_6H_4{-}CH_2^-}$
II. $\mathrm{C_6H_5{-}CH_2^-}$
III. $p$-$\mathrm{CH_3O{-}C_6H_4{-}CH_2^-}$
IV. $p$-$\mathrm{CHO{-}C_6H_4{-}CH_2^-}$
V. $p$-$\mathrm{CH_3{-}C_6H_4{-}CH_2^-}$
Choose the correct answer from the options given below:
Arrange the following carbanions in the decreasing order of stability:
I. $p$-$\mathrm{Br{-}C_6H_4{-}CH_2^-}$
II. $\mathrm{C_6H_5{-}CH_2^-}$
III. $p$-$\mathrm{CH_3O{-}C_6H_4{-}CH_2^-}$
IV. $p$-$\mathrm{CHO{-}C_6H_4{-}CH_2^-}$
V. $p$-$\mathrm{CH_3{-}C_6H_4{-}CH_2^-}$
Choose the correct answer from the options given below:
Show Hint
- IV $>$ I $>$ II $>$ V $>$ III
- I $>$ IV $>$ II $>$ V $>$ III
- I $>$ II $>$ IV $>$ V $>$ III
IV $>$ II $>$ I $>$ III $>$ V
The Correct Option is A
Solution and Explanation
Step 1: Stability principle for carbanions.
Carbanions are stabilized by electron withdrawing groups and destabilized by electron donating groups.
Step 2: Analysing substituent effects.
(IV) $-CHO$: Strong $-M$ and $-I$ effect, maximum stabilization.
(I) $-Br$: $-I$ effect dominates, stabilizing the carbanion.
(II) H: No substituent effect, moderate stability.
(V) $-CH_3$: $+I$ effect, destabilizes carbanion.
(III) $-OCH_3$: Strong $+M$ effect, maximum destabilization.
Step 3: Ordering stability.
\[ \text{IV}>\text{I}>\text{II}>\text{V}>\text{III} \] Step 4: Final conclusion.
The correct decreasing order of stability is IV $>$ I $>$ II $>$ V $>$ III, corresponding to option (1).
Top JEE Main Chemistry Questions
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)- At equilibrium the concentrations of and in a sealed vessel at . What will be for the reaction
- Find out the major products from the following reactions
Cobalt chloride when dissolved in water forms pink colored complex $X$ which has octahedral geometry. This solution on treating with cone $HCl$ forms deep blue complex, $\underline{Y}$ which has a $\underline{Z}$ geometry $X, Y$ and $Z$, respectively, are
- The correct order of atomic radii is:
Top JEE Main Questions
- In a hydrogen like atom, when an electron jumps from the $M$ - shell to the $L$ - shell, the wavelength of emitted radiation is $\lambda$. If an electron jumps from $N$-shell to the $L$-shell, the wavelength of emitted radiation will be :
- Two masses $m$ and $\frac{m}{2}$ are connected at the two ends of a massless rigid rod of length $l$. The rod is suspended by a thin wire of torsional constant $k$ at the centre of mass of the rod-mass system(see figure). Because of torsional constant $k$, the restoring torque is $\tau =k\theta$ for angular displacement $\theta$. If the rod is rota ted by $\theta_0$ and released, the tension in it when it passes through its mean position will be:
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)- The value of is
- The number of terms of an is even. The sum of the odd terms is and of the even terms is . The last term exceeds the first by . Then the number of terms in the series is ______.