Design an experiment to collect data that supports the claim that a 1.0m nacl solution is a homogenous mixture. describe the steps using these pieces of equipment:

ABSTRACT This module, one of 13 NYSCATE modules, features the integration of mathematics, science, and technology (MST) through an emphasis on design in the context of solutions and dilutions. Groups of students design, construct, and test a kit for measuring iron concentration that is to be used in Third World countries. The kit includes directions (standard operating procedure [SOP]), small-volume measuring devices, limited distilled water, and other materials. The procedure establishes a maximum percent error for the iron determinations. 

The answer is d.potassium