Please help! Chemistry questions involving pH and titration!?

A

anonymous

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1. Calculate the pH of a solution formed by mixing 65 mL of .19 M NaHCO3 with 75 mL of .23 m Na2CO3.

2. How many milliliters of .110 M HCl are needed to titrate each of the following solutions for quivalence point?
--40.0 mL of 9.50*10^-2 M NaOH.

Please help me and tell me how you did this step by step! Any helpful tips that will aid me in future similar problems are appreciated! Thank you in advance!
 
1. I don't know what reactants form when NaHCO3 and Na2CO3 are mixed. I need the equation to work this out.

2. NaOH + HCl -----> NaCl + H2O

Given 40.0 ml of 0.0950 mol/L NaOH is used.

To find the no. of moles of NaOH use:
1000ml of solution contains 0.0950 moles of NaOH
40.0 ml of solution will contain (0.0950/1000)*40.0 = 0.00380 moles of NaOH

Now, at equivalence point,
1 mole of NaOH will react with 1 mole of HCl (as per equation)
0.00380 moles of NaOH will therefore react with 0.00380 moles of HCl

Concentration of HCl used = 0.110 mol/L
So,
0.110 mol of HCl is found in 1000 ml of solution
0.00380 mol of HCl will be found in (1000/0.110)*0.00380 = 34.55ml of solution.

Volume of HCl needed to nutralise 40.0ml of 0.0950M NaOH = 34.55 ml
 
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