Ethyl benzene cannot be prepared by
Wurtz reaction
Wurtz-Fittig reaction
Friedel-Craft's reaction
Clemmensen reduction
Which one of the following is not true for the hydrolysis of t-butyl bromide with aqueous NaOH?
Reaction occurs through the SN1 mechanism
The intermediate formed is a carbocation
Rate of the reaction doubles when the concentration of alkali is doubled
Rate of the reaction doubles when the concentration of t-butyl bromide is doubled
Following is the substitution reaction in which -CN replaces -Cl.
R-Cl + R-CN + KCl
To obtaine propanenitrile, R-Cl should be
chloroethane
1-chloropropane
chloromethane
2-chloropropane
Which of the following is not true for SN1 reaction?
3°-alkyl halides generally react through SN1 reaction
The rate of the reaction does not depend upon the molar concentration of the nucleophile
1°-alkyl halides generally react through SN1 reaction
It is favoured by polar solvents
Match the reactant in Column I with the reaction in Column II.
Column I | Column II |
A. Acetic acid | i. Stephen |
B. Sodium phenate | ii. Friedel Crafts |
C. Methyl cyanide | iii. HVZ |
D. Toulene | iv. Kolbe's |
A - iii; B - i; C - iv; D - ii
A - iv; B - ii; C - iii; D - i
A - ii; B - iii; C - i; D - iv
A - iii; B - iv; C - i; D - ii
An incorrect statement with respect to SN1 and SN2 mechanisms for alkyl halide is
A strong nucleophile in an aprotic solvent increases the rate or favours SN2 reaction.
Competing reaction for an SN2 reaction is rearrangement.
SN1 reactions can be catalysed by some Lewis acids.
A weak nucleophile and a protic solvent increases the rate or favours SN1 reaction.
The hydrolysis of optically active 2-bromobutane with aqueous NaOH result in the formation of
(+) butan -2-ol
(-) butan-2-ol
(±) butan-1-ol
(±) butan-2-ol
D.
(±) butan-2-ol
In case of organic reactions, to differentiate between first order and second order kinetics, you should check the stability of carbocation. If carbocation is stable, then it will follow first order kinetics otherwise second order kinetics Since,2°- carbocation is stable so given reaction follows first order kinetics.
Usually 1° carbocatlon follows second order kinetics and 2° or 3° carbocation follows first order kinetics.The reaction between 2-bromobutane with aqueous NaOH follows first order kinetics, i.e the rate of the reaction depends upon the concentration of 2- bromobutane (SN1 mechanism).
Smee, the 2-bromobutane is optically active than the product is a racemic mixture. This is because carbocations are as intermediates in SN1 reactions Smee, carbocation being sp2 -hybridised is planar (achiral) species, the attack of the nucleophle on it can occur from both the faces (front and rear) with almost equal case giving a 50-50 mxture of two enantiomers. So, 2 bromobutane gives racemic of(±)butan-2-ol
Predict the product 'C' in the following series of reactions:
CH3-COOH
CH3CH(OH)C6H5
CH3CH(OH)C2H5
(CH3)2C(OH)C6H5
In Grignard reagent the carbon-magnesium bond is:
electrovalent
covalent
dative
hydrogen bonding