(a) If you were provided with anhydrous Na\(_2\)CO\(_3\), spatula and stirrer;
(i) list three other materials you would require to prepare a standard solution of Na\(_2\)CO\(_3\)
(ii) state what you would observe on adding diluted H\(_2\)SO\(_4\) to a portion of the Na\(_2\)CO\(_3\)
(b)(i) Describe briefly one chemical test you would perform to distinguish between zinc ions and aluminium ions in solution.
(ii) Mention one laboratory reagent you would use to;
I. produce ammonia from (NH\(_4\))\(_2\)SO\(_4\)
II. differentiate between precipitates of AgCl and Agl
lll. dehydrate ethanol
(c) Give the reason for each of the following laboratory practices
(i) Aqueous solutions of FeSO\(_4\) are freshly prepared when required for use.
(ii) The first jar of hydrogen collected during its preparation is discarded
Explanation
(a) - NaOH, filtration apparatus, source of heat, standard flask.
(ii) Effervescence occurs, CO\(_2\) from trioxocarbonate (IV) is given off.
(b)(i) To the solution of the substance, add potassium hexacyanoferrate (II) K\(_2\)Fe(CN)\(_6\) solution. A white ppt. confirms the presence of zinc ions or to the solution of the substance add few drops of ammonia solution, then add ammonium chloride solution. A white precipitate confirms the presence of aluminum ions
(ii)
(I) CaCO\(_3\)
(II) Aqueous ammonia
(III) Conc. H\(_2\)SO\(_4\)
(c)(i) FeSO\(_4\) easily undergo oxidation when left for some time.
(ii) The first jar contains a mixture of hydrogen and air.