## anonymous one year ago The weak acid HQ has pKa of 4.89. Calculate the (OH-) of 0.500 M HQ

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1. aaronq

First find $$[H^+]$$, then use $$\sf [H^+][OH^-]=K_w=1.0*10^{-14}$$

2. cuanchi

$pKa = -\log Ka => Ka = 10^{-pKa}$ $[H ^{+}]= \sqrt{Ka \times Ca}$ where Ca is the initial concentration of the acid assuming that the "x too small"