Question

1) Circle the better electrophile of each pair. NH, VS. BH, CH2Cl vs. CH3Br H30+ vs. HzC+ 2) Circle the better nucleophile of each pair. no vs. H₂O vs. NH3 ar vs. Br OH vs. SH

Answer 1

1) Nitrogen has an atomic number of 7 and an electronic configuration of 1s2, 2s2, 2p3. In an ammonium ion, nitrogen is bonded to hydrogen atoms and shares electrons with them. Due to all the orbitals to be fully filled and hence, nitrogen does not have space for any additional electrons. Thus, the ammonium ion is not an electrophile hence BH3 is better electrophile.

2)H3O+ can not gain electrons due to unavailability of vacant orbitals in their valence shell. H3O+ dissociates to give H2O and H+ , H+ can gain electron pair. ... H+ can gain electron pair and hence act as electrophile.hence CH3+ is better electrophile.

3) CH3Cl is better electrophile due to more electronegative nature of chlorine as compare to bromine attack ic effective in case of CH3Cl

4)CH3COO- is a nucleophile. It has a extra electron pair on the O- that can be donated.hence CH3COCH3 is better electrophile

Part 2)

NH3(Ammonia) has the stronger nucleophilic character than water molecule. Coz the Oxygen in the water molecule doesn't likely to bond with any carbon atom compared to Nitrogen atom. Since Oxygen has more electronegativity than Nitrogen. Hence it holds onto its lone pair tightly than Nitrogen

2) Br- is a better nucleophile than Cl-, but Br- is a better leaving group than Cl-. Because Br- is bigger than Cl- and hence better stabilize the negative charge, making it a better leaving group.

3) CH3CH2O- is better nucleophile because it has less electronegative than acetate ion.

4) Larger molecular radius hence outer electrons can be pulled off easier for SH-