25 ml of the given HCl solution requires 30 mL of 0.1 M sodium carbonate solution. What is the volume of this HCl solution required to titrate 30 mL of 0.2 M aqueous NaOH solution?

I HCl  Va = 25 ml  Na = ?  Na2CO3  Vb = 30ml  Mb = 0.1M  nb = 2  VaNa = VbNb  25Na = 30(0.1)2  Na = 6/25 NII HCl  Va = ?  Na = 6/25  NaOH  Vb = 30ml  Mb = 0.2M  nb = 1  VaNa = VbNb  Va(6/25) = 30(0.2)1  Va = 25 ml