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what actually farday predict about electric charge,would he measured the value of that.i could not understand that how he predict about the existence of charge on atomic particles from his experiment of electrolysis ?

Qandeel Noor Abbasi
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1 Answers1

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what actually Faraday predict about electric charge,would he measured the value of that.i could not understand that how he predict about the existence of charge on atomic particles from his experiment of electrolysis ?

$\def\NA{N_{\mathrm A}}$ He could only predict proportionality. In modern terms his two laws can be summarized by $$m = {Q\,M \over F\,z}$$ where

  • $m$ is the mass of substance deposited at one electrode
  • $Q$ is electric charge passed through the cell
  • $F$ is Faraday constant, actually $F=\NA e$ ($\NA$ Avogadro's constant, $e$ electron charge)
  • $M$ molar mass of substance deposited (old name, molecular weight)
  • $z$ ions charge, in units of $e$.

In terms of proportionality, Faraday's laws say

  • $m \propto Q$
  • $m \propto M$
  • $m \propto 1/z$.

$F$ at that time was simply a proportionality constant. As to $z$, it was related to chemical valence. E.g. for sodium $z=1$, for magnesium $z=2$. Both $M$ and $z$ were determined by chemical methods.

Elio Fabri
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