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प्रश्न
Which among the following are physical or chemical change?
Sublimation of solid ammonium chloride
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उत्तर
Physical
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संबंधित प्रश्न
Corrosion can be prevented by using ……………. solution.
Identify the substances that are oxidised and the substances that are reduced in the following reaction.
\[\ce{4Na(s) + O2(g) -> 2Na2O(s)}\]
Fill in the following blanks with suitable words:
The addition of hydrogen to a substance is called ........ whereas removal of hydrogen is called .......
You are given the following chemical equation:
Mg (s) + CuO (s) → MgO (s) + Cu (s)
This equation represents:
(a) decomposition reaction as well as displacement reaction
(b) combination reaction as well as double displacement reaction
(c) redox reaction as well as displacement reaction
(d) double displacement reaction as well as redox reaction
Fill in the blank
In redox reaction oxidation and reduction occur ............................
Define reduction.
The colours of aqueous solutions of CuSO4 and FeSO4 as observed in the laboratory are:
(A) pale green and light blue respectively
(B) light blue and dark green respectively
(C) dark blue and dark green respectively
(D) dark blue and pale green respectively
Identify from the reaction the reactants that undergo oxidation and reduction.
2Mg + O2 → 2MgO
Identify from the reaction the reactants that undergo oxidation and reduction.
\[\ce{NiO + H2 -> Ni + H2O}\]
Complete and balance the following equation:
\[\ce{K + H2O -> }\]________+ ________
State a reason why, when hydrogen is passed over heated copper oxide, the resultant product formed, differs in colour from the original reactant.
State what is reducing agent. Give an example of oxidising agent in the gaseous, liquid, and solid form.
Explain the following reaction with their balanced chemical equation.
Hydrogen sulphide reacts with sulphur dioxide.
What is a redox reaction?
Oxidizing agents are otherwise called ______.
The tarnishing of metals is due to the formation of ______.
The sum of the oxidation number of all atoms in a compound is ______.
Identify the following reactions as oxidation/reduction/redox reaction
CuO+H2 → Cu+H2O
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
