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सी.आई.एस.सी.ई.आयसीएसई ICSE Class 8

Explain the following type of chemical reaction, giving two examples for it: Decomposition reaction

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प्रश्न

Explain the following type of chemical reaction, giving two examples for it:

Decomposition reaction

स्पष्ट करा
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उत्तर

A reaction in which a compound breaks up due to heat application into two or more simple substances is called a decomposition reaction.

\[\ce{AB->[heat] A + B}\]
Examples:

  1. Mercuric oxide when heated, decomposes to form two elements mercury and oxygen
    \[\ce{2HgO_{(s)}->[heat] 2Hg_{(s)} + O2_{(g)}}\]
  2. CaCO3 when heated decomposes to calcium oxide and carbon dioxide.
    \[\ce{CaCO3 ->[heat] CaO + CO2}\]
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पाठ 6: Chemical Reactions - Exercise 2 [पृष्ठ ८६]

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सेलिना Concise Chemistry [English] Class 8 ICSE
पाठ 6 Chemical Reactions
Exercise 2 | Q 4.2 | पृष्ठ ८६

संबंधित प्रश्‍न

Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions.


Name the product formed on strongly heating ferrous sulphate crystals. What type of chemical reaction occurs in this change?


Two metals X and Y form the salts XSO4 and Y2SO4, respectively. The solution of salt XSO4 is blue in colour whereas that of Y2SO4 is colourless. When barium chloride solution is added to XSO4 solution, then a white precipitate Z is formed along with a salt which turns the solution green. And when barium chloride solution is added to Y2SO4 solution, then the same white precipitate Z is formed along with colourless common salt solution.

  1. What could the metals X and Y be?
  2. Write the name and formula of salt XSO4.
  3. Write the name and formula of salt Y2SO4.
  4. What is the name and formula of white precipitate Z?
  5. Write the name and formula of the salt which turns the solution green in the first case.

Give a scientific reason.

When the gas formed on heating limestone is passed through freshly prepared lime water, the lime water turns milky.


How can the rate of the chemical reaction, namely, decomposition of hydrogen peroxide be increased?


Give a balanced equation for –

An electrolytic decomposition reaction involving a neutral liquid


Give a balanced equation for –

A double decomposition neutralization reaction involving an acid and a base


Which among the following statement(s) is (are) true?

Exposure of silver chloride to sunlight for a long duration turns grey due to

(i) the formation of silver by decomposition of silver chloride.

(ii) sublimation of silver chloride.

(iii) decomposition of chlorine gas from silver chloride.

(iv) oxidation of silver chloride.


Write the molecular formula of calcium carbonate.


Write one equation for the decomposition reaction where energy is supplied in the form of electricity.


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