Unformatted text preview: Q 2. 31 Give the details for doing a specific test for H804. _
TRerwalﬁ M-JWLHSOQ 9M. 30’ rm Test for NO; Since all salts of NO; are highly water—soluble, NO; cannot be tested for by
precipitation. Instead, N 03' can be tested for by the combination of a redox reaction with a
reaction in which a colored complex ion is formed. (See p. 2-2.) In this test, NO; (if present)
will be reduced to NO as Fe(OH2)62+ is oxidized to Fe(0H2)63+. Simultaneously, NO will react
with Fe(OH2)62+ to produce Fe(OH2)5 (NO)2+ which is a brown complex ion. Place a single small crystal of Fe(OH2)6(NH4)2(SO4)2 in the hollow of a spot plate or in the
center of the shallow of a watch glass. Cover the crystal with a few drops of the test solution.
Immediately add two drops of concentrated (18 M) (HO)2302 (H2504)——HANDLE
18 M Hzﬁ)4 CAREFULLY! !_—allowing the H2804 to flow Without agitation to the
surface of the submerged crystal. If NO; is present in the test solution, a browu solution
(not a precipitate!) of Fe(OH2)5(NO)2+ will form on the surface of the crystal where the H2304 contacts it. Try the above test with 0.1 M NaNO3 and with a "blank", e.g., 0.1 M NaCl. Q 2.32 Describe observations and results for the above investigations. 442174. (QMCHO)Q.SOQ_ «2.92131221th
Mug e-gimmawo ML Vacate) (NHQiSoa); Q 2.33 Is it possible to test reliably for N0; in the presence of C1“? NH 4+ ?
SO 42’? Defend your answer. 3
OKQ—JJVHJ‘ M saga-W HaSOo tsaeieheﬂ—Izs
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- Spring '08