[MistaJones]

I've been working on these two questions and would like some assistance. 
The first question is

Molarity of HCL if 50mL is neutralized in a titration by 40.0 ml of .400M NaOH

Second question

10.1mL of HNO3 neutralized by 71.4 mL of 4.2 x 10^-3 M solution of KOH in a titration.  Calculate the concentration of the HNO3 solution

I'm half way through and I'm stuck

[english]

Neutralization implies that your acids are being completely consumed as they react with equivalent amounts of base.

If you know how much base was added, you also know how much acid reacted (in moles).


What other units of measure do you need to get the concentrations? 

[MistaJones]

Ah, I'm lost..I'm sorry

[DevaDevil]

the approach in these questions is as follows:

1. Calculate the number of moles of base titrated to the solution.

2. since the solution is neutralized (it has as much base added to it now as it had acid to start with), you now know how many moles acid there were in your solution

3. concentration is then calculated by it's definition: moles / volume.

[Borek]

First of all: write reaction equation.

[The Tao]

Just use the equation C₁V₁=C₂V₂

C₁(50ml)=(40.0 ml)(.400M)

C=(40.0)*(.400) / (50ml)

C= 0.32M