27. In the titration of Na, Co, by HCl using methylorange indicator, t

1.	27. In the titration of Na, Co, by HCl using methylorange indicator, the volume required at theequivalence point will be if that of the acidrequired using phenolphthalein indicator is10.0 ml:
Answer» Na2CO3 + HCl = NaHCO3 + NaCl Methyl-orange will change for the second protonation: NaHCO3 + HCl = H2CO3 + NaClH2CO3 = H2O + CO2 Either titration will tell you the amount of Na2CO3 you have. Combining both indicators is possible but since Methyl-orange is yellow on the basic side, it may obscure the transition of the phenophthalein (purple to colorless). If you were to use both, it would be best to add the methyl orange indicator after the first equivalence point when the phenophthalein has gone colorless. You would also have to remember to divide the concentration you get using two equivalents of acid by 2 to get the concentration of Na2CO3.

27. In the titration of Na, Co, by HCl using methylorange indicator, the volume required at theequivalence point will be if that of the acidrequired using phenolphthalein indicator is10.0 ml:

Answer»

Na2CO3 + HCl = NaHCO3 + NaCl

Methyl-orange will change for the second protonation:

NaHCO3 + HCl = H2CO3 + NaClH2CO3 = H2O + CO2

Either titration will tell you the amount of Na2CO3 you have.

Combining both indicators is possible but since Methyl-orange is yellow on the basic side, it may obscure the transition of the phenophthalein (purple to colorless). If you were to use both, it would be best to add the methyl orange indicator after the first equivalence point when the phenophthalein has gone colorless. You would also have to remember to divide the concentration you get using two equivalents of acid by 2 to get the concentration of Na2CO3.

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