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Form 4 Chemistry online lessons on acids, bases and salts

Measuring the strength of alkalis using electrical conductivity

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Answer Text:
Measuring the strength of alkalis Using electrical conductivity:
Procedure
50 $cm^3$ of 2 M sodium hydroxide solution is put into a beaker and the apparatus set as shown below
Apparatus
Procedure
-The same procedure is repeated using other alkalis like $NH_4OH$ ; $Ca (OH)_2$ e.t.c.
Observation
- The bulb lights brightly with KOH and NaOH as
electrolyte than with NH4OH and $Ca (OH)_2$
Explanation
- NaOH and KOH are strong alkalis and are completely dissociated and have more ions in solution and hence have got a higher electrical conductivity than the weak alkalis of NH4OH and $Ca(OH)_2$ (aq)