The pH of a sample of base is 12.7. The amount of crystalline oxalic acid required to react with 2 l of this solution is-
Is this a multiple choice question? What are the choices. It's done this way. You don't say what the base is but I will assume it is a strong base; therefore,
pH = - log (H^+)
12.7 = -log(H^+)
(H^+) = 2E-13. Then
(OH^-) = Kw/(H^+) = 1E-14/2E-13 = 0.05 molar base.
How many moles do you have in 2 L? That's mols = M x L = 0.05 x 2 = 0.1
Oxalic acid = H2Ox
...........H2Ox + 2OH^- ==> 2H2O + Ox^2-
........Y mols...+ 0.1 mol...............................
Therefore, mols H2Ox needed = 0.05 mol
mols H2Ox = grams H2Ox/molar mass. You know molar mass and mols, solve for grams H2Ox.
Post your work if you get stuck.
To determine the amount of crystalline oxalic acid required to react with 2 liters of the base solution, we need to consider the stoichiometry of the balanced chemical equation.
The balanced equation for the reaction between base and oxalic acid can be written as:
H2C2O4 + 2OH- → (COO)2- + 2H2O
Based on the equation, we can see that one mole of oxalic acid reacts with two moles of hydroxide ions. With this information, we can calculate the number of moles of hydroxide ions present in the 2-liter base solution.
First, convert the pH value of the base solution to hydroxide ion concentration:
pOH = 14 - pH = 14 - 12.7 = 1.3
Next, convert pOH to hydroxide ion concentration:
[OH-] = 10^(-pOH) = 10^(-1.3) = 0.0501 M
Now, determine the number of moles of hydroxide ions in 2 liters of solution:
mol OH- = [OH-] x volume (in liters) = 0.0501 M x 2 L = 0.1002 moles
Since it takes two moles of hydroxide ions to react with one mole of oxalic acid, we divide the number of moles of hydroxide ions by 2 to find the number of moles of oxalic acid required:
mol H2C2O4 = mol OH- / 2 = 0.1002 moles / 2 = 0.0501 moles
Therefore, the amount of crystalline oxalic acid required to react with 2 liters of the base solution is 0.0501 moles.