| 王国荣,袁万钟.电位法测定亚磷酸镍溶度积常数探讨[J].,2008,(6):800-803 |
| 电位法测定亚磷酸镍溶度积常数探讨 |
| Exploration of measurement of nickel phosphite′s solubility product constant by electric potential method |
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| DOI：10.7511/dllgxb200806004 |
| 中文关键词: 化学镀 镍-磷合金 亚磷酸镍 溶度积常数 |
| 英文关键词: chemical plating Ni-P alloys nickel phosphite solubility product constant |
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| 摘要点击次数: 1077 |
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| 中文摘要: |
| 用电位法测定了亚磷酸镍的溶度积常数log K 0． 首先设计了一个原电池，由半电池铂金-饱和甘汞电极和半电池镍-亚磷酸镍\5亚磷酸根组成，测出了不同亚磷酸根离子活度和不同温度下的原电池电动势，扣除了不同温度下饱和甘汞的电极电势，即得到镍-亚磷酸镍\5亚磷酸根的电极电势 E ．用 E 值通过Nernst方程式计算出亚磷酸镍的溶解、沉淀过程的活度平衡常数log K a，再用Debye-H?ckel方程式将log K a与离子强度联系起来，计算出log K d，用log K d-\%I\%作图，外推\%I\%趋近于零，求得了不同温度下的一组log K 0 值，当298 K(25 ℃)时，\{log K 0 =\}-4.33．再用log K 0 与热力学温度的倒数 (1/T) 作图，求得了亚磷酸镍溶解、沉淀过程的Δ H 和Δ S ，分别为-79.734 kJ\5mol -1 和184.655 J\5mol -1 \5K -1 ． |
| 英文摘要: |
| The measurement of nickel phosphite′s solubility product constant log K 0 by electrical potential method is explored. Firstly, a primary cell was designed, which is composed of a half-cell, platinum-saturated calomel electrode, and half-cell nickel-nickel phosphite\5phosphite. Different phosphite′s activity and the primary cell′s electromotive force under the conditions of different temperatures are measured, and electrode potential (E) of nickel-nickel phosphite\5phosphite is obtained by deducting the saturated calomel electrode potential. Then the activity equilibrium constant log K a of nickel phosphite′s solubilizing and precipitating process is calculated by means of value E and via Nernst equation. And then, log K a is connected with ionic strength (\%I\%) to calculate log K d by Debye-H?ckel equation. A picture of log \%K\% d-\%I\% is worked out, a group of values of log K 0 are obtained by extrapolating ionic strength (\%I\%) to zero. log K 0 is -4.33 when the temperature is 298 K (25 ℃). Again using log K 0 and the reciprocal of the thermodynamic temperature \%1T\% to work out a picture, the values of Δ H and Δ S in the nickel phosphite′s solubilizing and precipitating process are obtained, which are -79.734 kJ\5mol -1 and 184.655 J\5mol -1 \5K -1 respectively. |
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