Which is the concentration of NaOH(aq), in mol dm⁻³, that has pH = 14.30?
K_w = 1.00 × 10⁻¹⁴ mol² dm⁻⁶ at 25 °C - AQA - A-Level Chemistry - Question 32 - 2020 - Paper 3
Question 32
Which is the concentration of NaOH(aq), in mol dm⁻³, that has pH = 14.30?
K_w = 1.00 × 10⁻¹⁴ mol² dm⁻⁶ at 25 °C
Worked Solution & Example Answer:Which is the concentration of NaOH(aq), in mol dm⁻³, that has pH = 14.30?
K_w = 1.00 × 10⁻¹⁴ mol² dm⁻⁶ at 25 °C - AQA - A-Level Chemistry - Question 32 - 2020 - Paper 3
Step 1
Calculate the pOH from pH
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Answer
To find the concentration of NaOH, we first need to find the pOH from the given pH:
pOH=14−pH=14−14.30=−0.30.
Step 2
Calculate the concentration of OH⁻ ions
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Answer
Using the pOH, we can calculate the concentration of hydroxide ions, [OH⁻]:
[OH−]=10−pOH=10−(−0.30)=100.30≈2.00 mol dm⁻³.
Step 3
Select the correct option
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Answer
The concentration of NaOH that corresponds to the calculated [OH⁻] is 2.00 mol dm⁻³, which corresponds to option D.
