# Composition of a Mixture by Acid-Base Titration

1. Oct 4, 2007

### veena

A 1.00-g solid sample containing a mixture of table salt (NaCl) and citric acid (H3C6H5O7, a triprotic acid) is dissolved in 15 mL of water.
Titration of the acid solution requires 40.00 mL of 0.2003 M NaOH solution to reach the endpoint.
Calculate the mass percent H3C6H5O7 in the solid mixture.

Can somone plz explain how to do this problem...??

2. Oct 4, 2007

### chemisttree

Start by writing out the neutralization equation.

3. Oct 4, 2007

### veena

I have tried but i dont know how to solve for M2

M1 x V1 = M2 x V2

can u help plz

4. Oct 5, 2007

### chemisttree

Start by writing out the neutralization equation.

5. Oct 5, 2007

### AbedeuS

First, figure out how many moles of NaOH were used, this will be equivalent to the amount of $$OH^{-}$$ in the titration mixture, if its the end point $$OH^{-} = H^{+}$$, I hope that gets you closer to your final goal, as its bad policy for us to just give you a full answer.

Or, just do what chem said, write the neutralization equation (I do the more manual way personally ¬_¬ )

6. Oct 5, 2007

### symbolipoint

"triprotic acid".......... Which endpoint? Is your course "elementary chemistry" or is it undergraduate "Quantitative Chemistry"?

7. Oct 5, 2007

### AbedeuS

I think he will be reffering to the third endpoint, rather than the first.