Why are alkali metals not found in nature? from Chemistry The s
    • Zigya Logo

    The s-Block Elements
    pdf download
    zigya tab
    Explain why is sodium less reactive than potassium.
    Sodium is less reactive than potassium because ionisation enthalpy (∆H) of sodium (520 kJ mol–1) is more than that of potassium (496 kJ mot–1). Therefore it will lose electrons less readily as compared to potassium. 
    515 Views
    Answer

    When an alkali metal dissolves in liquid ammonia the solution can acquire different colours. Explain the reactions for this type of colour change.
    Or
    Explain why alkali metals dissolve in liquid ammonia to form deep blue solution.

    The dissolution of alkali metals in liquid ammonia is accompanied by the formation of ammoniated cations and ammoniated electrons as



    The blue colour of the solution is due to the ammoniated electrons.
    1523 Views
    Answer

    Find out the oxidation state of sodium in Na2O2. 

    Oxidation state of Oxygen Na2O2 is =(-1)
     Let x be the oxidation state of Na in Na2O2. Since peroxide linkage is present in Na2O2 in which the oxidation of O is –1.


    Hence oxidation state of Na in  is +1. 

    622 Views
    Answer
    Advertisement
    Zigya App

    Why are alkali metals not found in nature?

    Alkali metal has one electron each in the valence subshell of their atoms. Since they have only one electron in valence subshell, therefore, they lose easily, owing to their low ionisation energies. Therefore, alkali metals are highly reactive chemically and do not exist in the free or native state.

    1577 Views
  • zigya switch icon Switch
    • Advertisement

    Why is Li2CO3 decomposed at a lower temperature while Na2CO3 at higher temperature?

    Li2CO3 is a salt of a weak base (LiOH) and a weak acid (CO2). Since weak base can not attract CO2 strongly, therefore Li2CO3 decomposes at a lower temperature. also, the strong polarising action of small Li+ ion distorts the electron cloud on the nearby oxygen atom of the large CO32- ion. Thus, the C-O bonds get weakened and Li-O bonds become stronger which ultimately leads to the decomposition of lithium carbonate to oxide and carbon dioxide.



    On the other hand, Na    2CO3 is a salt of a strong base (NaOH) and a weak acid (H2CO3). Since NaOH is much stronger base than LiOH and hence can attract CO2 more strongly. Therefore Na2CO3 decomposes at much higher temperature because it is more stable than Li2CO3.
    403 Views
    Answer
    Advertisement
    Flag Popup Icon
    Flag it
    Submit
    Flag Popup Icon
    Switch to
  • Type
  • Category
    • flexipad
    Share It Icon
    Share it
    Share It
    Share it