Advertisements
Advertisements
Question
A shiny brown-coloured element ‘X’ on heating in air becomes black in colour. Name the element ‘X’ and the black-colored compound formed.
Advertisements
Solution 1
X’ is copper (Cu) and the black-coloured compound formed is copper oxide (CuO). The equation of the reaction involved on heating copper is given below.
\[\ce{2Cu + O2 ->[Heat] 2CuO}\]
Solution 2
The shiny brown-colored element is the copper metal (Cu). When the metal is heated in the air, it reacts with the atmospheric oxygen to form copper oxide. Hence, the black-colored compound is copper oxide, (CuO).
\[\ce{2Cu_{(s)} + O2_{(g)} ->[\Delta] 2CuO_{(s)}}\]
APPEARS IN
RELATED QUESTIONS
Corrosion can be prevented by using ……………. solution.
Define ‘redox reaction’. Give one example.
What is meant by rust?
Why is photosynthesis considered an endothermic reaction?
Explain the following in terms of gain or loss of oxygen with one example:
Reduction
Define reduction.
TRUE \ FALSE
Hydrogen is a good oxidizing agent.
Identify from the reaction the reactants that undergo oxidation and reduction.
2Mg + O2 → 2MgO
Is it essential that oxidation and reduction must occur side by side in a chemical reaction? Explain
State whether the following conversion is oxidation or reduction:
2Cl- - e-→ Cl2
With reference to oxidation & reduction reaction – complete the statement given by filling in the blanks with only the words (a) Addition (b) Removal.
‘Oxidation is a chemical reaction involving ____ of oxygen to a substance or ____ of hydrogen from a substance. Reduction on the otherhand involves ____ of hydrogen to a substance or ____ of oxygen from a substance.
Explain the term redox reaction with an example involving the reaction of hydrogen sulphide with chlorine.
Identify the oxidising agent (oxidant) in the following reactions
`"Pb"_3"O"_4 + 8"HCl" -> 3"PbCl"_2 + "Cl"_2 + 4"H"_2"O"`
Identify the oxidising agent (oxidant) in the following reactions.
`"CuO" + "H"_2 -> "Cu" + "H"_2"O"`
On adding a drop of barium chloride solution to an aqueous solution of sodium sulphite, white precipitate is obtained :
- Write a balanced chemical equation for the reaction involved.
- What other name can be given to this precipitation reaction?
- On adding dilute hydrochloric acid to the reaction mixture, white precipitate disappears. Why?
The tarnishing of metals is an example of ______ reaction.
Identify the following reactions as oxidation/reduction/redox reaction
CuO+H2 → Cu+H2O
Identify the following reactions as oxidation/reduction/redox reaction
2Mg +O2 → 2MgO
Find the oxidation number of the element in the following compound.
Ca in CaH2
