Abstract
<p> Ultraviolet absorbance spectra of ferric ions in 0.68 <em> m </em> NaClO <sub> 4 </sub> were studied as a function of pH at 4.0, 14.9, and 25.0°C. The results provided an evaluation of the stability constant for the formation of FeOH <sup> 2+ </sup> which is *β <sub> 1 </sub> =[ <em> FeOH </em> <sup> + </sup> ][ <em> H </em> <sup> + </sup> ]/[ <em> Fe </em> <sup> 3+ </sup> ]. The enthalpy change for the reaction Fe <sup> 3+ </sup> +H <sub> 2 </sub> O⇌ FeOH <sup> 2+ </sup> +H <sup> + </sup> was calculated as 10.0±0.3 kcal-mole <sup> −1 </sup> . Increasing temperature was also found to promote the reaction Fe <sup> 3+ </sup> +2H <sub> 2 </sub> O⇌ Fe(OH) <sup> + </sup> <sub> 2 </sub> +2H <sup> + </sup> . Our results were combined with the results of other to produce an expression describing the first hydrolysis equilibrium at ionic strengths between 0 and 3 <em> m </em> and temperatures between 4.0 and 45.0°C at 1 atm total pressure. At 25°C and 0.68 <em> m </em> the ionic strength *β <sub> 1 </sub> =1.90×10 <sup> -3 </sup></p>
Original language | American English |
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Journal | Journal of Solution Chemistry |
Volume | 7 |
DOIs | |
State | Published - Jan 1 1978 |
Keywords
- Ferric
- hydrolysis
- ionic strength
- temperature
- enthalpy
- ferric hydroxide
- ultraviolet
- spectroscopic
Disciplines
- Life Sciences