The following statement is correct: (1) Volcanoes erupted in Iceland and Indonesia, and volcanic ash could not settle in the air for several weeks, which may be related to the nature of colloid.

① Volcanic ash forms colloid in the air, and the colloidal particles have the same charge, and the same charges repel each other, so the colloid is stable, so ① is correct;

② 1mol glucose C6H 12O6, containing 6molC, 12molH, 6molO, can be fermented into 2mol lactic acid, so 1mol lactic acid contains 3molC, 6molH, 3mol, and the molecular formula of lactic acid is C3H6O3, so 1mol lactic acid.

③ Simple nonmetallic anions are generally the lowest-priced anions, which are only reduced; Metal cations are not necessarily just oxidation, for example, Fe2+ is both oxidation and reduction, so ③ is correct;

④ Electrolyte is ionized by water molecules in aqueous solution or ionized in molten state, which has nothing to do with electrification, so ④ is wrong;

⑤ When metal A is put into the salt solution of metal B, the reducibility of A is not necessarily stronger than that of B. For example, from 2FeCl3 +Cu=2FeCl2+CuCl2, copper is dissolved in the salt solution of iron, but the reducibility of copper is weaker than that of iron, so ⑤ is wrong;

So choose D.