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酸碱指示剂的变色范围

酸碱指示剂的变色范围. 酸碱指示剂的变色范围. 根据人眼对颜色的灵敏度： 酸式色时： [HIn]/[In - ]≥10 ， pH≤ p K HIn -1 碱式色时： [HIn]/[In - ]≤1/10 ， pH ≥p K HIn +1 混合色时： 10≥ [HIn]/[In - ] ≥1/10. 酸碱指示剂的变色范围. 指示剂的变色范围：人的视觉能明显看出指示剂由一种颜色转变成另一种颜色的 pH 范围。 指示剂的理论变色范围 : pH = p K HIn  1 指示剂的实际变色范围：实验测得的变色范围。一般小于 2 个 pH 单位。

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酸碱指示剂的变色范围

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  1. 酸碱指示剂的变色范围

  2. 酸碱指示剂的变色范围 • 根据人眼对颜色的灵敏度： 酸式色时：[HIn]/[In-]≥10，pH≤ pKHIn-1 碱式色时：[HIn]/[In-]≤1/10，pH ≥pKHIn+1 混合色时： 10≥ [HIn]/[In-] ≥1/10

  3. 酸碱指示剂的变色范围 • 指示剂的变色范围：人的视觉能明显看出指示剂由一种颜色转变成另一种颜色的pH范围。 • 指示剂的理论变色范围: pH = pKHIn  1 • 指示剂的实际变色范围：实验测得的变色范围。一般小于2个pH单位。 • 指示剂的理论变色点：当[In-]=[HIn]，pH = pKHIn时的pH。

  4. 酸碱指示剂的变色范围 • 在一定温度下不同指示剂的pKHIn不同，所以各指示剂的变色范围也不同。根据理论推算，其为两个pH单位。但实验测得的指示剂的变色范围并不都是两个pH单位，而是略有上下，这是由于人的眼睛对各种颜色的敏感程度不一样，加上两种颜色相互掩盖，所以实际变色范围与理论值存在有一定差别。

  5. 酸碱指示剂的变色范围 表9-1 常用的酸碱指示剂

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