Electrical Conductivity

[newbie_01]

Hi Everyone,

 

I just need some help putting the following in the order of most electrically conductive to least electrically conductive. Any help would be appreciated!

 

tap water

salt water

sugar water

vinegar

ammonia

bleach

[The Law]

haha, this is a pretty random question... well not random, but it's a poor way to test the concept. Anyway, I shall try to help!

 

I guess first we should identify what's being tested. Electrolytic substances are most conductive and these are substances that dissociate into ions easily.

 

Let's take a look @ the list and see:

 

Salt water <--obviously conductive, salt water is full of salt

Tap water <--a weak electrolyte, has some ions in it... but very very low [ ] of them

Sugar water <---less condutive, sugar is a very poor electrolyte as it does not dissociate easily

 

 

 

Vinegar, Bleach, and Ammonia - I don't really think it's important to discern which is the better electrolyte here (someone correct me if I'm wrong). Overall, they are all potentially electrolytic as all are weak acid/base molecules and will form ions in water.

 

 

 

if I had to categorize I'd probably say:

 

salt water > tap water > vinegar/ammonia/bleach (the ones with the higher Ka or Kb is the more electrolytic... and I'm pretty sure it'll be < than water so that's why I'm saying water is more electrolytic... but someone please let me know if this is wrong) > sugar water

 

Anyway - I'm not 100% sure, maybe someone else can comment who's more sure of the answer.

[The Ace of Spades]

Is the sugar dissolved in distilled water or tap water? If it is in tap water, then the difference in conductivity between the sugar water and the tap water will be negligible. If it is dissolved in distilled water, then it is less conductive than tap water. We'll assume that it's dissolved in distilled water, so that an actual order can be established.

 

Vinegar (aqueous acetic acid) and ammonia are weak acids/bases respectively. They will have poor conductance, but will have a greater ionic strength than tap water (as they are essentially in a tap water solution). Acetic acid is a stronger acid than ammonia is a base, so acetic acid will have the greater ionic strength.

 

The main ingredient in bleach is sodium hypochlorite, NaOCl. This is usually about 5% v/v. NaOCl will completely dissociate. Without knowing the concentration, we'll assume the salt water is saturated, >30% v/v.

 

With my assumptions (not unreasonable) in place, the following is the order of ionic strength - and conductivity:

 

Salt water > bleach > vinegar > ammonia > tap water > sugar water

 

Interestingly, if you combine the vinegar and ammonia, you'll have a solution even more conductive than the bleach. This is because any weak acid stronger than the ammonium ion will act as a strong acid in liquid ammonia, causing the acetic acid to completely dissociate. Vinegar is approximately 5% acetic acid, v/v.