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A 0.307-g sample of an unknown triprotic acid is titrated to the third equivalence point using 35.2 ml of 0.106 m naoh. calculate the molar mass of the acid. question 16 options:

Respuesta :

Triprotic acid is a class of Arrhenius acids that are capable of donating three protons per molecule when dissociating in aqueous solutions.  So the chemical reaction as described in the question, at the third equivalence point, can be show as: H3R + 3NaOH ⇒ Na3R + 3H2O, where R is the counter ion of the triprotic acid. Therefore, the ratio between the reacted acid and base at the third equivalence point is 1:3. 
The moles of NaOH is 0.106M*0.0352L = 0.003731 mole.  So the moles of H3R is 0.003731mole/3=0.001244mole.
The molar mass of the acid can be calculated: 0.307g/0.001244mole=247 g/mol.
mickymike92

Based on the nature of the acid as a triptotic acid, the molar mass of the acid is 247 g/mol.

What is a triprotic acid?

A triprotic acid is an acid which produces three moles of protons when dissolved in water.

The equation of the reaction at equivalence can be shown as follows;

H₃X + 3 NaOH ⇒ Na₃X + 3 H₃O

where X is the counter ion of the triprotic acid.

The ratio between the reacted acid and base at the third equivalence point = 1:3

The moles of substance reacted is calculated with the formula given below:

  • moles of substance reacted = molarity * volume

moles of NaOH reacted =  0.106M * 0.0352L = 0.003731 mole.

Thus, moles of H₃X reacted = 0.003731 moles /3

moles of H₃X reacted = 0.001244mole.

The molar mass of the acid can be calculated using the formula below:

  • molar mass =  mass /moles

molar mass of the acid = 0.307g / 0.001244mole

molar mass of acid = 247 g/mol

Therefore, the molar mass of the acid is 247 g/mol.

Learn more about molar mass at: https://brainly.com/question/15476873

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