(i) Account for the following: 1. White silver chloride turns grey in sunlight

CBSE Class 10 CBSE Class 10 Science
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(i) Account for the following:

  1. White silver chloride turns grey in sunlight.
  2. Brown coloured copper powder on heating in air turns into black coloured substance.

(ii) What do you mean by:

  1. Displacement Reaction?
  2. Reduction Reaction?
  3. Combination Reaction?
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(i) 1. Silver chloride turns grey on exposure to sunlight because it decomposes in presence of sunlight to give silver (Ag).
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2. Oxidation of copper powder gives black colour copper oxide.

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(ii) 1. Displacement reaction: A reaction in which a more reactive element displaces a less reactive elements from its salt sodium.
Example: Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s)
2. Redaction Reaction: Addition of hydrogen or removal of oxygen is called reduction.
Example: ZnO + C → Zn + CO
3.Combination Reaction: A reaction in which two or more reactants combine to give a single product.
Example: CaO(s) + H20(l) → Ca(OH)2(aq)