19,000+ solved questions for JEE Advanced, JEE Mains, NEET & IChO — with answers and expert explanations.
Assertion: In SN1 mechanism, the product with inversion of configuration is obtained in a higher amount compared to the product with the retention of configuration. Reason: Front side attack of nucleophile is hindered…
Assertion: Heavy metal ions Ag + or Pb 2+ decrease SN1 reactivity. Reason : They aid ionisation of RX.
Assertion: Rate of reaction is dependent only on the concentration of nucleophile in SN1 reactions. Reason: Polar solvent favors SN1 reaction.
Assertion: Consider the following SN2 reactions. (I) and (II) Reaction (II) occurs at a faster rate than (I) Reason: Anion of reaction (II) is a stronger base than the anion of reaction (I).
Assertion: Allyl halide (CH2=CH–CH2X) is more reactive than CH3CH2CH2X in a SN2 reaction. Reason: Allyl halide forms a resonance stabilized carbocation
Assertion: SN2 reaction of CH3––Br is faster in Cl CH S – SCH3 Cl (CH ) CHS 3 2 – SCH(CH ) 3 2 DMSO than in H2O. Reason: DMSO has greater capability to solvate nucleophile.
Assertion: Chlorination of allylic hydrogen is difficult than vinylic hydrogen. Reason: Allyl radical is stabilised by resonance.
Assertion: Treatment of either enantiomer of 2-chlorobutane with ethanolic KOH results in trans-2- butene as major elimination product. Reason: Elimination with ethanolic KOH is a bimolecular reaction.
Assertion: Ph–CO–CH2CH2OCH3 has greater reactivity for E1CB than for E2 reaction. Reason: A poor leaving group and acidic —H favour E1CB mechanism.
Assertion: The reaction of bulky base such as potassium tertiary butoxide [(CH3)3CO–K+] with secondary alkyl halides gives predominantly E2 elimination product rather than SN2 substitution product. Reason: The transit…
Assertion: p-nitrochlorobenzene is more reactive than m-nitrochlorobenzene towards aromatic nucleophilic substitution reaction. Reason: Nitro group from para and meta positions has opposite effect in aromatic nucleoph…
Assertion: A dichlorobenzene is slightly more reactive than chlorobenzene towards an aromatic nucleophilic substitution reaction. Reason: Chlorine has electron withdrawing effect on aromatic ring.
Assertion: Chloral reacts with phenyl chloride to form DDT. Reason: It is an electrophilic substitution reaction
Formation of free radical takes place with absorption of minimum energy in the formation of : (a) (b) (c) (d)
The rate of SN1 reaction is fastest with: (a) (b) (c) CH Br CH NO2 Br (d)
Which of the following compounds will undergo SN1 reaction? (a) (b) (c) (d)
Which one of the following will give racemised product in C2H5OH? (a) (b) (c) (d)
This reaction would follow which of the following pathway predominantly?
The order of reactivities of the following alkyl halides for a SN2 reaction is
Major product of the following reaction is: (a) (b) (c) (d)
(a) (b) (c) (d)
This reaction would follow which of the following pathway predominantly?
C6H6Cl6 is six membered cyclic compound in which each carbon carry one chlorine atom, on treatment with alcoholic KOH yields
1-pentene will be formed as major product when methoxide reacts with
What is true about the following reaction? (a)Only substitution product is formed. (b)Only elimination product is formed. (c)Both substitution and elimination products are formed and substitution dominates. (d)Both su…