A student titrated a solution containing 3.7066 grams of an unknown triprotic acid to the end point using 28.94 milliliters of 0.3021 M KOH. What is the molar mass of the unknown acid? And write a balanced equation for the reaction.

You don't say to which end point the triprotic acid was titrated. It could be titrated to the first H, the second, or all three. I will assume all three H ions were neutralized.

H3A + 3KOH ==> K3A + 3H2O

moles KOH = M x L = ??
Using the coefficients in the balanced equation, convert mole KOH to moles H3A. That will be ??moles KOH x (1 mole H3A/3 moles KOH) = (1/3) x moles KOH.
Then moles H3A = grams H3A/molar mass H3A. YOu know moles and grams H3A, solve for molar mass.

1272

To find the molar mass of the unknown triprotic acid, we need to use the balanced equation for the reaction and stoichiometry.

Let's consider the balanced equation for the reaction between the unknown triprotic acid (HA) and potassium hydroxide (KOH):

HA + 3KOH → K3A + 3H2O

From the equation, we can see that each mole of HA reacts with 3 moles of KOH.

Given:
Mass of unknown triprotic acid (HA) = 3.7066 grams
Volume of KOH used = 28.94 mL = 0.02894 L
Concentration of KOH = 0.3021 M

First, we calculate the number of moles of KOH used:
Number of moles of KOH = concentration × volume
= 0.3021 M × 0.02894 L
= 0.008750974 mol

According to the balanced equation, the stoichiometric ratio between HA and KOH is 1:3. Therefore, the number of moles of HA can be calculated as:
Number of moles of HA = (Number of moles of KOH) / 3
= 0.008750974 mol / 3
= 0.002916991 mol

Next, we calculate the molar mass of the unknown acid (HA) using the formula:
Molar mass (g/mol) = mass (g) / number of moles
= 3.7066 g / 0.002916991 mol
= 1271.35 g/mol

Therefore, the molar mass of the unknown triprotic acid is approximately 1271.35 g/mol.

The balanced equation for the reaction is:
HA + 3KOH → K3A + 3H2O

To find the molar mass of the unknown triprotic acid, you can follow these steps:

Step 1: Calculate the moles of KOH used.
The volume of the KOH solution used is given as 28.94 milliliters, which is equivalent to 0.02894 liters.
The concentration of the KOH solution is given as 0.3021 M (moles per liter).
Using the formula:
moles of KOH = volume (L) × concentration (M)
moles of KOH = 0.02894 L × 0.3021 M

Step 2: Calculate the moles of the triprotic acid.
Since the acid is triprotic, it requires three moles of KOH for every mole of the acid reacted.

moles of triprotic acid = (moles of KOH) / 3

Step 3: Calculate the molar mass of the triprotic acid.
The molar mass is given by the formula:

Molar mass = mass of the acid (g) / moles of the acid

In this case, the mass of the acid is given as 3.7066 grams.

molar mass of the triprotic acid = 3.7066 g / (moles of the triprotic acid obtained from Step 2)

To write a balanced equation for the reaction, based on the stoichiometry, we know that:

1 mole of triprotic acid reacts with 3 moles of KOH.

Therefore, the balanced equation for the reaction is:
3 HA + 3 KOH → K3A + 3 H2O
where HA represents the triprotic acid and K3A represents the salt formed.