Are the following True or False? If false, explain why. (I put what I think the answers are below each question)
1) Iron metal will reduce Fe3+ to Fe2+
(False because Fe3+ is more stable than Fe2+?)
2) Copper metal will dissolve in nitric acid, liberating NO gas
(True)
3) Oxygen in moist air can oxidize I- to I2
(True)
4) Silver metal will dissolve in HNO3 but not HCl
(True)
5)Gold may be dissolved in 1M HNO3
(False because gold is a strong oxidizing agent, stronger than HNO3)
1) False. Iron metal can indeed reduce Fe3+ to Fe2+.
2) False. Copper metal does not dissolve in nitric acid, and it does not liberate NO gas.
3) True. Oxygen in moist air can oxidize I- to I2.
4) True. Silver metal will dissolve in HNO3 but not HCl.
5) False. Gold can actually be dissolved in 1M HNO3.
1) True. Iron metal can reduce Fe3+ to Fe2+ because Fe2+ is a lower oxidation state and is more stable than Fe3+.
2) False. Copper metal will not dissolve in nitric acid to liberate NO gas. Nitric acid is a strong oxidizing agent and can react with copper to produce nitrogen dioxide (NO2) gas, not nitric oxide (NO) gas.
3) True. Oxygen in moist air can indeed oxidize I- to I2, especially in the presence of a catalyst such as an enzyme or a metal ion.
4) True. Silver metal will dissolve in HNO3 (nitric acid) but not HCl (hydrochloric acid). Nitric acid has a strong oxidizing property that facilitates the dissolution of silver, while hydrochloric acid does not.
5) False. Gold is a noble metal and is highly resistant to oxidation, so it does not dissolve in most acids, including 1M HNO3 (nitric acid).
1) The statement is true. Iron metal can indeed reduce Fe3+ to Fe2+. This is because iron has a higher reducing power compared to Fe3+. The reaction can be represented as follows: Fe(s) + Fe3+(aq) → Fe2+(aq). The resulting Fe2+ ions are more stable in aqueous solution than Fe3+ ions.
2) The statement is false. Copper metal does not dissolve in nitric acid to liberate NO gas. Copper is not reactive enough to directly react with nitric acid. However, concentrated nitric acid in the presence of heat can oxidize copper metal, leading to the formation of copper(II) ions and the evolution of NO2 gas. The reaction can be represented as follows: 3Cu(s) + 8HNO3(aq) → 3Cu(NO3)2(aq) + 2NO2(g) + 4H2O(l).
3) The statement is true. Oxygen in moist air can indeed oxidize iodide ions (I-) to elemental iodine (I2). This reaction can be observed by the color change from colorless to brown as iodine is formed. The reaction can be represented as follows: 2I-(aq) + O2(g) + 2H2O(l) → I2(s) + 4OH-(aq).
4) The statement is true. Silver metal does dissolve in concentrated nitric acid (HNO3) but not in hydrochloric acid (HCl). The presence of chloride ions in HCl can form a protective layer of insoluble silver chloride on the silver surface, preventing further dissolution. However, nitric acid can react with silver to form soluble silver nitrate. The reaction can be represented as follows: Ag(s) + 2HNO3(aq) → AgNO3(aq) + H2O(l) + NO2(g).
5) The statement is false. Gold cannot be dissolved in 1M HNO3 because gold is an unreactive metal and is not easily oxidized. Nitric acid (HNO3) is a strong oxidizing agent, but it is not strong enough to oxidize gold. Therefore, gold does not react with 1M HNO3.