Answer:
pH = 2.
Explanation:
A weak acid is in equilibrium with its ions in a solution, so it must have an equilibrium constant (Ka). And, pKa = -logKa
Ka = 10⁻⁴
So, for CH₃COOH the equilibrium must be:
CH₃COOH(aq) ⇄ H⁺(aq) + CH₃COO⁻(aq)
1 M 0 0 Initial
-x +x +x Reacted
1-x x x Equilibrium
And the equilibrium constant:
Supposing x << 1:
10⁻⁴ = x²
x = √10⁻⁴
x = 10⁻² M, so the supposing is correct.
So,
pH = -log[H⁺]
pH = -log10⁻²
pH = 2
Answer:
Mass of Analyte H2C2O4 = 18.18 grams
Explanation:
The balanced equation is:
The Molarity of Oxalic acid needed can be determined using:
Here M1 = Molarity of Oxalic acid
V1 = Volume of oxalic acid
M2 = Molarity of KOH and V2 = Volume of KOH
M1 = ? , V1 = 16.8 mL , M2 = 0.501 M , V2 = 13.54 mL
Put the values and solve for M2,
We are multiplying by 2 because , 1 H2C2O4 needs 2 KOH
Hence Molarity of H2C2O4 =
0.202 M
Molar mass = H2C2O4 = 2x1 +2x12 + 4x16
= 2+24+64 = 90 gram
18.18 gram
