Determine which choice(s) is/are correct? i. stirring slows down (decreases) rate of dissolution. ii. grinding solids increases their surface area of contact. iii. heating slows down (decreases) rate of dissolution. iv. grinding solids speed up their rate of dissolution. a) i, ii, and iii b) ii and iv c) i and iii d) iii and iv

Answer B- II and IV.

Grinding the solids increases their surface area of contact with the solvent. Hence this results in increased rate of dissolution. Also by grinding the large particles into smaller pieces,the resistive power is reduced and this results in increased rate of dissolution.

Example normal sugar dissolves faster in a solvent than a sugar cube due to reduced contact surface  area with the solvent.