Mechanisms of substitution reactions (SN1/SN2)
- Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).Assertion (A) : (primary alkyl iodide drawn as zig-zag chain ending in I) undergoes S_N2 reaction faster than (the corresponding alkyl chloride,… Answer: 1. Both A and R are true and R is the correct explanation of A Key idea: in S_N2 the rate depends on how easily the leaving group de... 1
- The compound that will undergo S_N1 reaction with the fastest rate is Answer: 1. [structure: 1-bromoethylbenzene (phenyl-CH(CH ₃ )-Br), see figure] Key idea: S_N1 rate depends on carbocation stability. 1-Bromoe... 1
- Consider the reactionCH_3CH_2CH_2Br + NaCN → CH_3CH_2CH_2CN + NaBrThis reaction will be the fastest in Answer: 2. N,N' -dimethylformamide (DMF) Key idea: this is an S_N2 reaction on a primary halide, which is fastest in a polar aprotic solvent... 1
- For the following reactions :(a) CH_3CH_2CH_2Br + KOH → CH_3CH=CH_2 + KBr + H_2O(b) (CH3)2CHBr + KOH -> (CH3)2CHOH + KBr (structures shown in figure)(c) cyclohexene + Br_2 -> 1,2-dibromocyclohexane (structures shown in figure)Which of the following s… Answer: 2. (a) is elimination, (b) is substitution and (c) is addition reaction. Key idea: identify what happens to the substrate. (a) CH₃CH... 1