Question

A solution contains na2co3 and NaHCO3 15ml of the solution required 5 mLN/10 of for neutralization using phenolphthalein as an indicator. With methyl orange indicator, 15 mL of the acid is required for neutralization. The amount of na2co3 present in one litre of the solution is:

Answer 1

Na2CO3 + HCl -> NaHCO3 + NaCl

NaHCO3 + HCl -> H2O + CO2(g) + NaCl

The volume of HCl used to titrate each 25mL of Na2CO3 is of 50mL.

Therefore, if you want to titrate 25mL of Na2CO3, you'll have to use a volume of The Volume of HCl is twice than the volume of Na2CO3.

Therefore,For 20.5 mL of HCl, amount of Na2CO3 is

20.5/2 = 10.25 mL.