The concentration of hydroxide ion is 5
10^ − 14 M.
Step-by-step explanation:
Consider the equilibrium of this acid's dissociation,
H C l O 4 ⇌ H + + C l O 4 -
Moreover, let's assume that H C l O 4 is a strong acid and will fully dissociate.
Hence,
[ H + ] = 0.20 M
Now, recall,
K w = [ H + ] [ O H − ] = 1.0
10 ^− 14
Hence,
⇒ [ O H − ] = K w / [ H + ] = 5
10^ − 14 M.