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Explain the following: a. Alkali metal...

Explain the following:
a. Alkali metals are paramagnetic, but their salts are diamagnetic.
b. The inside surface of a glass bottle containing caustic sada becomes dull.

Text Solution

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a. The general electronic congiguration of alkali metals is `ns^(1)`, i.e. alkali metals have one unpaired etectron in their valence shells and hence they are paramagnetic. Alkali metal salts are ionic in nature, i.e. alkali metals lose the valence shell electron to form unpiositive cation and non-metal acceprt this electrons to form uninegative ion and thus all the electrons are paired up and hence alkali metal salts are diamagnetic.
b. Glass contains silica. It slowly dissolves in NaOH and forms soluble sodium silicate and thus the inside surface becomes dull.
`2Naoh+2sIo_(2)rarr 2NaSiO_(3)+H_(2)`
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CENGAGE CHEMISTRY ENGLISH-S-BLOCK GROUP 1 - ALKALI METALS-Ex 4.1 (Subjective)
  1. Why superoxides of of alkali metals are paramagnetic ?

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  2. Alkali metals are paramagnetic but their salts are dimagnetic. Explain...

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  3. Give reasons for the following. LiI has lower melting point than LiF...

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  4. The Haber process can be represented as follows

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  5. Why does the reaction. proceed better with KF than with NaF ?

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  6. why lithium is kept wrapped in paraffin wax and not stored in kerosene...

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  7. When is a cation highly polarising? Which alkali metal cation has the ...

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  8. Why cesium can be used in photoelectric cell, while lithium cannot be ...

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  9. Give reason for the decreasing order of the conductivity of the follow...

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  10. NaHCO(3) and NaOH cannot exist together in solution. Why ?

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  11. On exposure to air, sodium hydroxide becomes liquid and after sometime...

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  12. Alkali metals are obtained by the electrolysis of the molten salts and...

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  13. What happens when: a. Potassium metal is dropped in water b. Potas...

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  14. How is sodium carbonate manufactured by Solvay's process? Draw a schem...

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  15. a. Describe one method of manufacture of castic soda. b. What happen...

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  16. Answer the following: Give the name of the hardest alakli metal.

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  17. Explain the following: a. Alkali metals are paramagnetic, but their ...

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  18. Identify (A) and (B) in the following: KO(2)+S overset(Delta)rarr (A)...

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  19. LiOH has been used by astronauts. Explain the use with the help of rea...

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  20. Give the composition and action of backing powder.

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