Scoring scheme: 3-3-2-1 question 1b) an unknown solution could contain any or all of the following cations: k+, ca2+, cr3+, mn2+, fe3+, co2+, zn2+. a 1 ml portion of the unknown is treated with 2 ml of 6 m naoh, added a few drops at a time with shaking. immediately thereafter, 10 drops of 3% hydrogen peroxide are added dropwise with shaking, and the test tube is then heated for a few minutes in a water bath until bubbling ceases. the resulting conglomerate is then centrifuged and the supernatant liquid is decanted off and saved. (although you have not demonstrated these facts for yourself, ca2+ will be precipitated as the hydroxide at this stage and k+ will remain in the decanted liquid.) at this stage of the experiment which elements could be found in the precipitate? select all that apply.