please help me with these question

Chemistry
Tutor: None Selected Time limit: 1 Day

A 10.0-mL sample of pineapple juice was titrated with 0.100 M sodium hydroxide solution. the average volume of NaOH required to reach the endpoint was 12.8 mL


a.Calculate the number of moles of sodium hydroxide required to reach the endpoint


answer:


b.Using the mole ratio for the neutralization reaction shown in equation 1, determine the number of moles of citric acid in 10.0 mL of the of pineapple juice.

Apr 29th, 2015

DATA:

Volume of citric acid= 10.0mL

Concentration of NAOH= 0.1M

Volume of NaOH= 12.8mL

Moles of NaOH at end point= ?

Moles of citric acid/10.0mL= ?

SOLUTION:

C6H8O7 + 3NaOH รจ Na3C6H5O7 + 3H2O

MOLES OF NaOH:

1000.0mL of NaOH contains 0.1 mol Of NaOH

12.8mL of NaOH contains (0.1*12.8)/1000

  =1.28*10-3 mol of NaOH

MOLES OF CITRIC ACID:

3NaOH = 1 C6H8O7

1.28*10-3 = (1*1.28*10-3)/3

  = 4.2666*10-4 mol of C6H8O7/10.0mL

ANSWER:

Moles of NaOH at end point= 1.28*10-3 mol of NaOH

Moles of citric acid/10.0mL=4.2666*10-4 mol of C6H8O7


Apr 29th, 2015

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Apr 29th, 2015
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Apr 29th, 2015
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