how are you able to tell if a compound produces many, few, or no ions when dissolved in water?

Question

Doing an at home lab about conductivity for my chemistry online class which is separate from the current lesson being taught..

You must dissolve compounds such as NaCl, CaCl₂.. etc into water and record whether it is a strong/weak or nonelectrolyte and if many, few or no ions are produced in the water.

thank you in advance :)

Answer 1

The key here is if the compound is a strong electrolyte, it will dissociate completely giving many ions. If a weak electrolyte, it will dissociate partially giving not so many ions, and if it is a non electrolyte it will not dissociate at all giving no ions.

How do you know? If it is a salt of a non metal and a metal (NaCl, CaCl², etc.), it is a strong electrolyte. In this case, NaCl gives Na⁺ and Cl^- and CaCl² give Ca²⁺ and 2 Cl^-, so you see that one mole of CaCl₂ produces 3 moles of ions whereas 1 mole NaCl produces 2 moles of ions.

If you have a weak acid or a weak base, e.g. acetic acid (CH3COOH) or ammonia (NH3), then the dissociation is partially and you will get a few ions, but not too many depending on the Ka or Kb.

If you have something like glucose, or sucrose or many other organic molecules, they do not dissociate or ionize at all and so are non electrolytes producing no ions.

Answer 2

It would appear from the information that you provided that something is missing. Simply dissolving a substance in water will not tell you if it is an electrolyte or a non-electrolyte, only if it is soluble.

What does it mean when you say that something is an electrolyte or a non-electrolyte? The short answer is that it conducts electricity. Non-electrolytes are solutions which do not conduct electricity. The degree to which a solution is a strong or weak electrolyte is determined by how much electricity is conducted. The following diagram at https://chemconnections.org/crystals/ppt/reactions/img003.gif illustrates the difference.