Err on the side of high rather than low pH. If necessary, continue to add dilute ammonium hydroxide until the pH is in the range 7-8. Do not dip the paper into the solution (contamination) but instead touch the edge of the paper on the wet side of the glass rod that has been dipped in the solution. When you think that precipitation is complete, check by using Universal Indicator Paper to measure the pH, which should be in the range 7-8. The bis(dimethylglyoxime) complex of nickel(II) will begin to precipitate. Stir the solution continuously with a glass rod and add dropwise dilute (3 M) ammonium hydroxide. At this temperature, REMOVE THE BEAKER FROM SOURCES OF IGNITION then add dimethylglyoxime (1% solution in ethanol, 30 cm 3 ). Cover the beaker with a watch glass (convex side down) and heat the solution to about 70☌ using a hotplate. Dissolve the sample in deionised water (100 cm 3), add concentrated hydrochloric acid (3 cm 3 ), then make the total volume of the solution up to ca. Weigh out (BF 4) 2 (0.25 g) using a crude top loading balance and transfer into a beaker (either 400 cm 3 or 600 cm 3). Perhaps if you posted a method people could break it down for you.
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