If you end up within 0.3 percentage points of a higher grade, if you answer this

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If you end up within 0.3 percentage points of a higher grade, if you answer this question correctly, you can be awarded the higher grade. There is a five minute timer, and only one try will be allowed.

A niacin vitamin tablet specifies that each tablet contains 100 mg nicotinic acid. A student looking for extra credit in general chemistry lab asks the instructor if it is OK if the vitamin tablet is titrated to determine if the amount the manufacturer claims to be there is correct. Two tablets are crushed and combined, and together weigh 0.3813 g, and require 18.80 mL of 0.1000 M NaOH to titrate to the equivalence point.

The ingredients list on the bottle indicates that dicalcium phosphate, microcrystalline cellulose, modified cellulose gum, magnesium stearate, stearic acid and calcium silicate are present. Would the experimental percent nicotinic acid be too high, too low, unaffected, or can’t be determined?

A. too low

B. can't determine

C. too high

D. unaffected

Explanation / Answer

The experimental percent nicotine acid be too high.answer is C.

Stearic acid is also present in tablet.It also reacts with NaOH.So moles of NaOH required for titration increases.So moles of acid increases.

At equivalence point, moles of acid = moles of base.

As moles of acid is more weight of nicotinic acid obtained is more.so experimental percent nicotinic acid is too high.

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