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A. Answer the following questions.1.What happens when-a. Hydrogen is passed over red hot copper oxide.b. Hydrogen reacts with molten sulphur.c. Zinc reacts with dilute hydrochloric acid.d. Calcium reacts with cold water |
| Answer» <p>a) Metallic copper and water vapour will be formed when hydrogen is passed over heated copper(II) oxide.</p><p>CuO + H2 = Cu + H2O</p><p>Hydrogen reduces cupric oxide to free metal in this reaction.</p><p>b) Hydrogen gas will react with molten sulfur (around 450*C) to form gaseous hydrogen sulfide, H2S. It has a characteristic smell of rotten eggs, is poisonous, flammable and corrosive. Some bacteria in our gut will produce H2S under certain circumstances.</p><p>c)Thereactionbetweenzincandhydrochloric acidisZn+HCl= H2 + ZnCl2. It is a single replacementreactionwherezincmetal displaces the hydrogen to form hydrogen gas andzincchloride, a salt.Zinc reactsquickly with the acid to form bubbles of hydrogen.</p><p>d) In the following demonstration, a chunk ofcalciummetal is dropped into a beaker of distilledwater. After a second or so, thecalciummetal begins to bubble vigorously as itreactswith thewater, producing hydrogen gas, and a cloudy white precipitate of calciumhydroxide.</p><p>Like my answer if you find it useful!</p> | |