Enter the formula and state of the major species that result when a few grams (about 0.01 mol) of each substance is added to 100 mL of water. When appropriate use water to form species such as the hydronium ion. Separate multiple species by commas.
rubidium dihydrogen phosphate
rubidium chlorate
rubidium hydrogen carbonate
cobalt(II) hydroxide
Actually, I don't know how to answer these questions for I don't know what is meant by major. However, here is what I think.
RbH2PO4 will dissociate in water to form primarily Rb^+(aq) and H2PO4^-(aq)
RbClO4 dissociates in water to form Rb^+(aq) and ClO4^-(aq)
RbHCO3 to form Rb^+(aq) and HCO3^-(aq)
Co(OH)2(s) isn't soluble in water so the MAJOR specie is Co(OH)2(s)