Abstract: In a method for the electrical measurement of the concentration of acids a measurement electrode (11) consisting at least predominantly of crystalline graphite is arranged in an acid (12) having anions which form graphite intercalation compounds with graphite. The measurement electrode (11) is then intercalated by generating in the measurement electrode (11), at a variable positive potential, a current of such a size that the anions of the acids (12) can from graphite intercalation compounds with the graphite. The current is maintained until the intercalation compounds have formed at the surface. The potential at the measurement electrode (11) is then measured and used as a measure for the acid concentration. The measurement electrode (11) is subsequently deintercalated again.

Abstract: The invention relates to a cathodically depositable aqueous electropaints which contain cationic amine-modified epoxy resins and are pigmented, with electroconductive carbon black and which, on deposition and crosslinking, provide electrophoroetically overcoatable coatings and contain as electroconductive carbon black a carbon black having an iodine absorption of 870-930 mg/g, a specific surface area (BET/N.sub.2) of 850-1,000 m.sup.2 /g, a pore volume (DBP) of 330-390 ml/100 g and an average particle size of 25-35 nm in an amount of 1.5 to 5.1% by weight--based on total solids.

Abstract: The invention relates to cathodically depositable aqueous electropaints which contain cationic amine-modified epoxy resins and are pigmented with electroconductive carbon black and which, on deposition and crosslinking, provide electrophoretically overcoatable coatings and contain as electroconductive carbon black a carbon black having an iodine absorption of 870-930 mg/g, a specific surface area (BET/N.sub.2) of 850-1,000 m.sup.2 /g, a pore volume (DBP) of 330-390 ml/100 g and an average particle size of 25-35 nm in an amount of 1.5 to 5.1% by weight - based on total solids.

Abstract: Cyclic hemiacetals thereof of the formula ##STR1## where A is saturated hydrocarbyl of 2 to 16 carbon atoms which may contain --O-- as a bridge member are prepared by subjecting cyclic ethers of the formula ##STR2## where A has the abovementioned meaning, to anodic oxidation in aqueous solution at current densities of over 30 mAcm.sup.-2.

Abstract: In a secondary battery employing an aqueous lead salt solution as the electrolyte, salts of manganese, cobalt, nickel, copper, thallium, bismuth and/or antimony are additionally present in concentrations of from 0.1 to 100 mmole/l.

Abstract: An accumulator having an acid electrolyte and possessing two electrodes of the first kind mounted on base electrodes. The active material on the positive side contains manganese dioxide. The base electrode on the negative side consists of powdered graphite embedded in a binder which is resistant to the electrolyte. The base electrode on the positive side has a coarse porous structure and consists of graphite or titanium coated with titanium nitride or titanium carbide. The average pore diameters are from 0.1 to 2 mm and the pore volume is from 20 to 70%.

Abstract: Secondary batteries with aqueous acid solutions of lead salts as electrolytes and inert electrode base plates also contain redox systems in solution. These systems have a standard potential of from -0.1 to +1.4 V relative to a standard hydrogen reference electrode, do not form insoluble compounds with the electrolytes and are not oxidized or reduced irreversibly by the active compositions applied to the electrode base plates, within their range of operating potentials.

Abstract: Accumulators having solution electrodes containing manganese dioxide and lead dioxide as active material on the cathode side and containing acid electrolytes. The electrolyte has a content of onium salts soluble in aqueous medium.

Abstract: An electrochemical cell with a nonpartitioned electrolyte chamber and plane electrodes, which form a stack, the chamber filled by the electrolyte forming narrow gaps between the electrodes, and the electrode stack being assembled on a fixed baseplate so that its axis is essentially vertical.

Abstract: Lead batteries which contain lead salt solutions and/or their corresponding acids and have a titanium base plate on the positive electrode and a graphite base plate on the negative electrode.

Abstract: Pinacol is manufactured by electrolytic hydrodimerization of acetone in a compartmented cell using a catholyte which contains from 10 to 90% by weight of acetone, from 1 to 60% by weight of water and from 1 to 50% by weight of a quaternary ammonium salt.