Assume that the acidic protons in Tang titrated are either from vitamine C in th

Question

Assume that the acidic protons in Tang titrated are either from vitamine C in the Tang crystals, or from the polyprotic citric acid (molar mass 192.12g/mol; each citric acid molecule reacts with three NaOH) in the Tang crystals.

1. Calculate the number of moles of acidic protons attributable to citric acid per gram of Tang titrated.

2. From the answer to 1, calculate the number of moles of citric acid per gram of Tang titrated.

I titrated 25.66mL of NaOH which had a molarity of 0.0502M. I also used 2.017g of Tang.

Explanation / Answer

1] 25.66 ml of 0.0502 M used of NaOH

moles of NaOH =1.288*10^-3 moles

no of molecule of NaOH used = moles*Na =25.66*10^-3*0.0502*6.023*10^23

=7.758*10^20 molcules

this is the total no of acidic protons present in Tang =7.758*10^20 molcules

as vitamin C contain 4 acidic protons and citric acid 3

moles of NaOH used by citric acid = [3/7]* 1.288*10^-3

=5.52*10^-4 this is alos the moles of acidic protons attributable to citric acid per 2.017 gram of Tang titrated

so per 1 gm of tang the moles of acidic protons attributable to citric acid

= 5.52*10^-4/2.017 =2.736*10^-4 moles

2] as one molecule of citric acid contain 3 protons so no of moles of citric acid per gram of tang = 2.736*10^-4/3=9.12 *10^-5 moles   

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