Ask Question
24 July, 17:57

Ka for hcn is 4.9 ⋅ 10-10. what is the ph of a 0.068 m aqueous solution of sodium cyanide? ka for hcn is 4.9 10-10. what is the ph of a 0.068 m aqueous solution of sodium cyanide? 0.74 7.00 2.96 13.24 11.07

+4
Answers (1)
  1. 24 July, 18:37
    0
    Answer is: pH of solution of sodium cyanide is 11.07.

    Chemical reaction 1: NaCN (aq) → CN ⁻ (aq) + Na⁺ (aq).

    Chemical reaction 2: CN ⁻ + H₂O (l) ⇄ HCN (aq) + OH⁻ (aq).

    c (NaCN) = c (CN ⁻) = 0.068 M.

    Ka (HCN) = 4.9·10⁻¹⁰.

    Kb (CN ⁻) = 10⁻¹⁴ : 4.9·10⁻¹⁰ = 2.04·10⁻⁵.

    Kb = [HCN] · [OH ⁻] / [CN⁻ ].

    [HCN] · [OH ⁻] = x.

    [CN ⁻] = 0.068 M - x ...

    2.04·10 ⁻⁵ = x² / (0.068 M - x).

    Solve quadratic equation: x = [OH ⁻] = 0.00116 M.

    pOH = - log (0.00116 M) = 2.93.

    pH = 14 - 2.93 = 11.07.
Know the Answer?
Not Sure About the Answer?
Get an answer to your question ✅ “Ka for hcn is 4.9 ⋅ 10-10. what is the ph of a 0.068 m aqueous solution of sodium cyanide? ka for hcn is 4.9 10-10. what is the ph of a ...” in 📙 Chemistry if there is no answer or all answers are wrong, use a search bar and try to find the answer among similar questions.
Search for Other Answers