91Ó°ÊÓ

a)ethoxide ion gives a higher substitution-product-to-elimination-product ratio when it reacts with isopropyl bromide because elimination is favoured by bulkier base and tert-butoxide ion is bulkier than ethoxide ion.

b) ^-SCN gives a higher substitution-product-to-elimination-product ratio when it reacts with isopropyl bromide because elimination is favoured by stronger base and ^-OCN is stronger base than ^-SCN.

c) Br^-gives a higher substitution-product-to-elimination-product ratio when it reacts with isopropyl bromide because elimination is favoured by stronger base and Cl^-is stronger base than Br^-.

d) CH₃S^- gives a higher substitution-product-to-elimination-product ratio when it reacts with isopropyl bromide because elimination is favoured by stronger base and CH₃O^- is stronger base than CH₃S^-.