Chemistry acid-base question?

For a 0.1mol/L of monoprotic weak acid (HA) at a certain temperature, the ratio between the unionized and ionized molecules is 50:2, find the value of ionization constant (Ka) for the acid, HA.

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  • 5 months ago
    Best answer

    Use the Ka equation:

    Take the acid as HA

    This will dissociate :

    HA ↔ H+ + A-

    Ka = [H+] [A-] /[HA]

    Because dissociation is very small we can use 0.1M for [HA]

    [H+] = 2/50*0.1 = 0.0004M

    [A-] = 0.0004M

    Ka 0.0004 * 0.0004 / 0.1

    Ka = 1.6*10^-5 * 0.1

    Ka = 1.6*10^-4

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