Please someone help me in SN1 and SN2 . I know that in case of primary alkyl halides SN1 is followed only in case of solvolysis. Like CH3X in H2O. But i want to know other cases when SN1 is followed in primary RX. Like when we use weak nucleophile and polar solvent with primary alkyl halide it will follow SN1 or SN 2?

Polar aprotic solvents are solvents that share ion dissolving power with protic solvents but lack an acidic hydrogen. These solvents generally have high dielectric constants and high polarity.

Examples are dimethyl sulfoxide, dimethylformamide, dioxane and hexamethylphosphorotriamide.

Polar protic solvents are favorable for SN1 reactions, while polar aprotic solvents are favorable for SN2 reactions. Apart from solvent effects, polar aprotic solvents may also be essential for reactions which use strong bases, such as reactions involving Grignard reagents or n-butyl lithium. If a protic solvent were to be used, the reagent would be consumed by a side reaction with the solvent.

and the easiest way to find wether sn2 or sn1 is performing is that first form carbocation by removing the leaving group and check the degree of carbocation i.e by rearrangement check the possibility of degree of carbocation formed if it is forming one degree carbocation after rearrangement also then sn2 is favoured if it is 2 degree then sn1 will form the major product and sn2 will give minor product and if 3 degree then sn1 is favoured 

pls approve by clicking yes below