Briefly describe a simple laboratory experiment or reaction to confirm the following trends going down groups of the Period Table.
(i) The group 1 element potassium is more reactive than sodium.
(ii) The group 7 element bromine is less reactive than chlorine.
your answers should include the names of the reagent(s) , the observations and an equation for the reaction.
Question about the reactive element
2007-01-04 1:18 am
回答 (2)
2007-01-04 3:15 am
✔ 最佳答案
(i) When sodium reacts with water, it melts to form a silvery ball and moves rapidly on the surface of water. However, potassium reacts with water more vigorously than sodium and catches fire.2Na + 2H2O → 2NaOH + H2
2K + 2H2O → 2KOH + H2
(ii) Chlorine reacts with hydrogen slowly, and bromine reacts with hydrogen only on heating.
Cl2 + H2 → 2HCl
Br2 + H2 → 2HBr
參考: me
2007-01-04 4:01 am
(i). When potassium is put in water, it floats on the water surface and move more vigorously than sodium. A louder hizzing sound is produced by potassium than sodium. Potassium catches lilac flame while sodium does not.
2K(s) + 2H2O(l) → 2KOH(aq) + H2(g)
2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)
(ii). Prepare potassium bromide solution and a chlorine solution. When chlorine solution is put in the potassium bromide solution, the colour of the solution turns from colourless to brown. This shown that bromide ion is displaced by the more reactive chloride ion.
2KBr(aq) + Cl2(aq) → 2KCl(aq) + Br2(aq)
2K(s) + 2H2O(l) → 2KOH(aq) + H2(g)
2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)
(ii). Prepare potassium bromide solution and a chlorine solution. When chlorine solution is put in the potassium bromide solution, the colour of the solution turns from colourless to brown. This shown that bromide ion is displaced by the more reactive chloride ion.
2KBr(aq) + Cl2(aq) → 2KCl(aq) + Br2(aq)
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