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Dissociation constant

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A TGD-approved handbook states that the notional solid structure has a dissociation constant of 3.6 at 25°C, suggesting that at the ambient pH of 3.6, half the gluconic acid molecules will exist in the form of the uncharged acid, and half as the anion.  At pH < 3.6, the undissociated form will predominate, and pH > 3.6 the anion will predominate.  Therefore, gluconic acid will exist predominantly in the form of the dissociated anion throughout the range of pH 4 to 9. 

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Additional information

Information regarding dissociation constant of 50% aqueous solution of gluconic acid was based on the notional solid structure and was sourced from two separate handbooks. Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals (14th Ed.) and Ullmann's Encylopedia of Industrial Chemistry (7th Ed.) report that gluconic acid (free acid) has a dissociation constant of 3.6 and 3.7 at 25°C, respectively. Although the information from both sources is comparable, the data obtained from Ullmann’s handbook is not TGD-approved, and as such is of Klimish-4 reliability and is not considered valid.