(a) Metals react with oxygen to give basic compounds of oxygen. Barium oxide,BaOis a basic oxide which is soluble in water.
(b) KOH is highly soluble in water, K+ion will form most water-soluble hydroxide because it is the most reactive of these metals and thus forms strong alkali KOH which will undergo complete dissociation in water, thus making it highly soluble.
(c) Metals react with oxygen to give basic compounds of oxygen. Copper (II) oxide, CuO is a basic oxide which is insoluble in water.
(d) Berrylium hydroxide, Be(OH)2is insoluble in water but will dissolve in alkalis.
(e) A weak mineral acid is that which partially dissociates into its ions in an aqueous solution or water and derived from one or more inorganic compounds. Carbonic acid, H2CO3 is weak mineral acid.
(f) A base is a chemical species that donates electrons, accepts protons, or releases hydroxide ions in an aqueous solution. Alkalis are those bases that can dissolve in water while those which don't dissolve in water are not alkali. Copper (II) hydroxide Cu(OH)2is a base which is not an alkali.
(g) Metals react with oxygen to give basic compounds of oxygen. Sodium oxide is a base.
(h) An acid is any hydrogen-containing substance that is capable of donating a proton (hydrogen ion) to another substance. Methane,CH4 is not acid as proton are covalently bonded to carbon, so it will not be able to donate a proton.