H2C2O4 * 2H2O (s) is a primary standard substance. 2.3688 grams of oxalic acid dihydrate were completely neutralized by 42.56 milliliters of NaOH solution. Calculate the molar concentration of the NaOH solution.
H2Ox + 2NaOH ==> 2H2O + Na2Ox
moles H2Ox = grams/molar mass
Convert moles H2Ox to moles NaOH using the coefficients in th balanced equation. That will give you moles NaOH = 2 x moles H2Ox.
Then M NaOH = moles NaOH/L NaOH.
. H
2
C
2
O
4
.2H
2
O(s) is a primary standard substan
ce. 2.3688 g of oxalic acid dihydrate
were completely neutralized by 42.56 ml
of NaOH solution. Calculate the molar
concentration of the NaOH solution. Hint:
You must write a balanced equation for the
react
To calculate the molar concentration of the NaOH solution, we need to use the stoichiometry of the neutralization reaction between oxalic acid dihydrate (C2H2O4 * 2H2O) and sodium hydroxide (NaOH).
The balanced equation for the reaction is:
C2H2O4 * 2H2O + 2NaOH → 2NaC2O4 + 4H2O
From the equation, we can see that 1 mole of oxalic acid dihydrate (C2H2O4 * 2H2O) reacts with 2 moles of sodium hydroxide (NaOH).
Step 1: Find the molar mass of oxalic acid dihydrate.
The molar mass of C2H2O4 is:
(2 * atomic mass of carbon) + (2 * atomic mass of hydrogen) + (4 * atomic mass of oxygen)
C2H2O4: (2 * 12.01 g/mol) + (2 * 1.008 g/mol) + (4 * 16.00 g/mol) = 90.03 g/mol
The molar mass of C2H2O4 * 2H2O is the molar mass of C2H2O4 plus the molar mass of 2 water molecules (2 * 18.02 g/mol).
C2H2O4 * 2H2O: 90.03 g/mol + (2 * 18.02 g/mol) = 126.07 g/mol
Step 2: Calculate the number of moles of oxalic acid dihydrate (C2H2O4 * 2H2O) used in the reaction.
The number of moles can be calculated using the formula:
moles = mass / molar mass
moles = 2.3688 g / 126.07 g/mol = 0.0188 mol
Step 3: Calculate the number of moles of NaOH that reacted.
From the balanced equation, we know that 1 mole of C2H2O4 * 2H2O reacts with 2 moles of NaOH. Therefore, 0.0188 mol of C2H2O4 * 2H2O will react with (2 * 0.0188) = 0.0376 mol of NaOH.
Step 4: Calculate the molar concentration of NaOH.
The molar concentration (in mol/L or M) can be calculated using the formula:
Molarity = moles of solute / volume of solution (in L)
Molarity = 0.0376 mol / 0.04256 L = 0.884 M
Therefore, the molar concentration of the NaOH solution is 0.884 M.