Question

1. Which of the following takes place faster by an S2 reaction! 2. Rank from strongest nucleophile to weakest nucleophile. A HO B. HO C. HN D. H 3. Which of the following SN2 reactions is fastest? , (o) (a) H3C-CECH Na NaH CHBr (SN2) сH,Br (b) Naci (S2) 4. Which of the following takes place faster by an E2 mechanism? ONa 5. Which is the best leaving group? A. F" B. CI C. HO D. Br E. H

Answer 1

[ Answer 1. Answer: Reach" om (a) take place faster by 3N2reach on Explanahon In reach on Cas Cyclohexyl co oxide is nucleophile The Cyclohexyl oxide is stronges nucleophile than phenocide The phenocide is weak nucleophile because -ve charge onto- atom undergoes delocalization into the phenyl ring by --Relbert ols fing and it is not easily available for attack. There luce reachiom caj take place faster than reachon (b). GOON Nae + ore. - col strong nudeophile Fastes reachcm - of Br Toro weak nucleophort Cu slower Reaction strongest nucleophile weakest nucleophile NHL > Hooy tho) Ho strong weak Nih is stronger nucleophile than one because N-atom is less electronegative than meygen and there wore it easily donate the -ve charge on it. Hoo is stronger than to becowe -vely charged Spaçies are alwoay stronger nucleuphile than there neutral molecule. The donahon os -ve change place than lome pair of electron. Hho is weak nuclerphile because oxygen is more electronegahve atom ond it. strongly bind lome pais electocons present on it.

3.) Answer Reachio (a) is Fastest SNP reachions (a) C-CEC-H NOH → C-Eco S90, Cif-CE011 Strong Nucleophile Fastest sN 2 Reachon The acetylide is stronger nucleophile than cle. The ce is weak nucleophile as compared with acetylide anion. Therekore reachion cal is faster than reach cor (b). () Cly-Br + Nad och slowest SNP reach.com 4) Answer: In the presence of stronger nucleophile, elimination reach on in aikyl halide proceed at via El mechanism. As nature of nucleophile changes from weak to stoc g, the rate ob E2 reach an increases Reachoom cal take place fastes by an El mechanism. Because Cyclohescyloseide is stronger nucleo phile. On other hand teachin (6) take place slow as compared to reaction (b). In reach or (b) phenocide is weak nucleophile (a) CI+ Cogna a strong Faster Nucleophuile (b) o I+ @ Jona - slowest weak nucleophile

(5) Answer Bre is best teaving group. Among the Fecie Hoe Brelo Boo is best Jeaving group. Bre i's stable and it is conjugate base strong acid HBr. The conjugate base ols strong acid act as good leaving group. The Fo and die gre the conjugate bases of weak acid HF and Hel. Both ate Small size atom a compared with Br atem. Un large size of atom, polarizah on of -ve change is ebbsechvely occurs and the leaving group is act as good leaving group. Hoe is very bad leaving group and it is coniugate base of wea stest aed to.