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प्रश्न
A reddish brown metal used in electrical wires when powdered and heated strongly turns black. When hydrogen gas is passed over this black substance, it regains its original colour. Based on this information answer the following questions:
- Name the metal and the black substance formed.
- Write balanced chemical equations for the two reactions involved in the above information
उत्तर
- The metal is called copper (Cu), and the black substance generated is called copper oxide.
- The balanced chemical reactions for both the reactions are as follows:
When powdered copper is heated strongly in the presence of oxygen copper oxide is.
\[\ce{2Cu(s) + O_2(g) ->[\Delta]2CuO(s)}\]
When hydrogen gas is passed over copper oxide, it produces copper metal and water.
\[\ce{CuO(s) + H_2(g) ->Cu(s) + H_2O(l)}\]
APPEARS IN
संबंधित प्रश्न
Explain oxidation in terms of gain or loss of oxygen with one example.
In the reaction represented by the following equation:
CuO (s) + H2 (g) → Cu (s) + H2O (1)
(a) name the substance oxidised
(b) name the substance reduced
(c) name the oxidising agent
(d) name the reducing agent
Identify from the reaction the reactants that undergo oxidation and reduction.
Fe + S → FeS
Give the general group study of hydrogen with reference to
burning
Divide the following reactions into oxidation and reduction half-reaction:
Zn + Cu2+ → Cu + Zn 2+
Name:
an oxidizing agent that does not contain oxygen.
State the condition and give balanced equation for the conversion of coke to water gas.
Rusting of iron involves a chemical reaction which is a combination of:
Identify the oxidising agent (oxidant) in the following reactions.
`"CuO" + "H"_2 -> "Cu" + "H"_2"O"`
A silver article generally turns black when kept in the open for a few days. The article when rubbed with toothpaste again starts shining.
- Why do silver articles turn black when kept in the open for a few days? Name the phenomenon involved.
- Name the black substance formed and give its chemical formula.
