Activity Series of Metals

The activity series of metals is a list of metals arranged in the order of their decreasing chemical activity. The most active metal, potassium is placed at the top of the list and the least active metal, platinum is at the bottom. Activity series of metals is also referred to as reactivity series of metals or electrochemical series. Metals like sodium and potassium are so reactive, that they are stored in kerosene. More reactive metals have greater tendency to lose electrons. So, they are more electropositive or more metallic in nature. The most electropositive metal occurs at the top and the least electropositive metal occurs at the bottom of the activity series. Metals lying above in activity series can displace the metals lying below from their salt solutions. The reducing power of metals decreases on moving down the activity series. Hydrogen is included in the activity series even though it is not a metal because hydrogen ion (H+) like other metal ions has a positive charge in most of the chemical reactions. Metals react with oxygen (from air) to form metal oxides. Metals lying above hydrogen in activity series displace hydrogen from water. Metal oxides placed below aluminium in activity series can be reduced by heating in the presence of reducing agents. Metals react with dilute acids to form metal salt and hydrogen gas. Metal carbonates and metal nitrates placed below sodium in activity series decompose on heating.

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  • Q1

    One of the products formed when calcium hydroxide heated is calcium oxide. The other product will be

    Marks:1
    Answer:

    H2O

    Explanation:

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  • Q2

    The gas liberated when magnesium reacts with dilute hydrochloric acid is

    Marks:1
    Answer:

    H2

    Explanation:

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  • Q3

    Zinc reacts with oxygen

    Marks:1
    Answer:

    on strong heating.

    Explanation:

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  • Q4

    A metal that reacts vigorously with cold water is

    Marks:1
    Answer:

    K

    Explanation:

    Potassium is the most reactive metal in the reactivity series. Hence, it reacts vigorously with cold water.

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  • Q5

    The metal obtained by the electrolysis of its fused halide or oxide is

    Marks:1
    Answer:

    Ca

    Explanation:

    Highly active metals upto aluminium in the activity series are obtained by the electrolysis of their fused halides or oxides as their oxides cannot be reduced by common reducing agents such as carbon, carbon monoxide etc.

    Calcium is placed above aluminium in the activity series. Hence, it is obtained by the electrolysis of its fused halide or oxide.

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