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PH of salts

  1. Oct 12, 2004 #1
    Here's another I wanna just check with you

    The pH of 0.01M Methylammonium chloride (not from the last thread)is lower than 7, correct? As Methylammonium is a weak base and HCl a strong acid?

    The pH of potassium cyanide will 7? Both KOH and HCN are very strong?

    And finally, the pH of sodium methanoate. This is greater than 7 as Sodium Hydroxide is a strong base and Methanoic acid a weak acid with the OH- predominating?

  2. jcsd
  3. Oct 12, 2004 #2
    Do you know the pH scale?

    The pH of potassium cyanide will 7,

    No 7 is netrul, 7+ = basic, 7- = acidic.

    The pH of potassium cyanide will be = 11 (0.1 N aqueous solution). Use 11.

    pH of sodium methanoate = 8-9.5

    Methylammonium chloride = 8 (0.1N)
  4. Oct 12, 2004 #3


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    I think it is very close to 7 or 6; according to the neutral point of the water sample used (carbondioxide free water gives a plain 7 pH value, I think).

    No. HCN is a very very weak acid, so the pH is even greater than KOH; cyanide is a very strong base since there is a very reactive three-bonded carbon with a non-bonded electron pair.

    Yes, this is okay.
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