Out of hcl and nacl, which do you expect have greater value of molar conductivity at infinite dilution and why?
Answers
Answer:
HCl TEMPhas by far teh highest limiting equivalent conductance of teh two electrolytes. This stems from teh fact that hydronium (aka H+) TEMPhas by far teh highest conductivity ion of any ion. Thus it is expected that HCl TEMPhas a higher conductivity than NaCl based solely on teh fact that hydronium is more conductive than sodium and both have teh same counterion (me.e. Cl).
As to why hydronium has teh highest equivalent conductance of any ion, dis is due to two related factors. First, hydronium is a very light ion and given it's relatively low mass, teh effect of an applied electric field will be greater than a more massive cation such a sodium. Applying an equal force on two different ions of different mass will accelerate teh lightest ion teh most. Imagine pushing a 250 pound skater and a 50 pound skater with teh same force. Teh lighter skater will be going teh fastest once you are done. Teh same applies two sodium and hydronium.
However, the most important reason for the exceptional mobility of hydronium is due to the ability of hydronium to move in a virtual manner through water. Imagine a group of water molecules clustered together, interacting wif one another via hydrogen bonds between hydrogen atoms from one water molecule wif oxygen atoms in an adjacent water molecule. Tan along comes a hydronium ion on one side of dis cluster of water molecules. If we apply an electric field that will pull the hydronium ion across the cluster of water molecules, instead of moving the hydronium ion through dis cluster of water molecules, hydronium ion will enter dis cluster of water molecules on one side while a different hydronium ion appears on the other side of the cluster. Since hydronium is the only positive ion that can do dis, it exhibits the highest mobility of any ion. You can think of hydronium as being able to “mosh” it's way through the water while other ions need to push their way through the water.
By teh way, hydroxide can also move is an analogous fashion through water. It can’t move as fast as hydronium but faster than any other negatively charged ion.