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प्रश्न
With reference to Water explain with suitable examples of how the reactivity of the metals could be differentiated.
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उत्तर
Action of metals with water: K, Na, Ca react with cold water.
K: Darts on the water surface and react violently.
Na: Revolves on the water surface and bums.
Ca: Sinks in water, react less violently.
Hence, K > Na > Ca calcium is less reactive than K and Na.
Mg and Al react with boiling water/steam.
Hence, Mg and Al are less reactive than K, Na, and Ca. Zn, Fe, Pb also react with steam and reaction stops soon. Fe when hot reacts with steam
This shows that Mg > Al > Zn > Fe > Pb.
Cu, Hg, Ag, Pt, Au do not react with steam or even when hot is less reactive.
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संबंधित प्रश्न
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A metal that exists as a liquid at room temperature is obtained by heating its sulphide in the presence of air. Identify the metal and its ore and give the reaction involved.
A metal M does not liberate hydrogen from acids but reacts with oxygen to give a black colour product. Identify M and black coloured product and also explain the reaction of M with oxygen.
Explain the following
- Reactivity of Al decreases if it is dipped in HNO3
- Carbon cannot reduce the oxides of Na or Mg
- NaCl is not a conductor of electricity in solid state whereas it does conduct electricity in aqueous solution as well as in molten state
- Iron articles are galvanised.
- Metals like Na, K, Ca and Mg are never found in their free state in nature.
Arrange the following as per the instruction given in the bracket:
Al, K, Mg, Ca (decreasing order of its reactivity)
