Abstract
Various factors (temperature, concentration, pH etc.) are expected to influence on the rate of decomposition of sodium percarbonate.
In this paper, we investigated the influence of the change in pH on the decomposition.
Results are summarized as follows :
1) The rate of decomposition of sodium percarbonate in the solution varied remarkably with the change in pH. In the acidic range, sodium percarbonate did not decompose practically, whereas, in the pH range of 7.0-10.5, the decomposition became rapid as the pH rose and marked maximum at pH 10.5.
Above pH 10.5, however, it appeared that the decomposition tended to be suppressed.
2) The addition of copper salt into the solution of sodium percarbonate accelerated the decomposition of the percarbonate, comparing with the absence of this salt. Particularly, this tendency was remarkable when pH was above 11.
3) As to the relation between the bleaching ability (here, decoloration) of sodium percarbonate and the pH of the solution, in the areas above pH 7.0, decoloration by percarbonate was noticeable as the pH value rose up more than pH 7.0.
4) The addition of copper salt into the solution of sodium percarbonate increased slightly the bleaching ability in the areas above pH 7.0, comparing with the case of nonaddition of this salt.
