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500 " mL of " a solution contains 2.65 g of `Na_2CO_3` and 4 g of `NaOH`. 20 " mL of " this solution titrated each time against `(N)/(10)H_2SO_4`. Find out the titre value if (a). Methyl orange is taken as an indicator (b). Phenolphthalein is taken as indicator. |
Answer» `Na_2CO_4` in `1L=2xx2.65=5.3g` `NaOH` in `1L=2xx4=8g` Normality of `Na_2CO_3=(5.3)/(53)=0.1N` Normality of NaOH`=(8)/(40)=(1)/(5)N` `N_1V_1(H_2SO_4)=N_2V_2(Na_2CO_3)` `(N)/(10)xxV_1=20xx0.1N` `V_1=20cc` `N_1V_1(H_2SO_4)=N_2V_2(NaOH)` `(N)/(10)xxV_1=(N)/(5)xx20` `V_1=(1)/(5)xx20xx10=40cc` With methyl orange as an indicator: Full titre value of NaOH`+` Full titre value of `Na_2CO_3` `=40+20=60cc` With phenolphthalein as an indicator: Full titre value of `NaOH+(1)/(2)` titre value of `Na_2CO_3=40+10=50c c` |
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