A 010 M Solution of a Weak Monoprotic Acid Has a a Hydronium-Ion

question 27

Multiple Choice

A 0.10 M solution of a weak monoprotic acid has a hydronium-ion concentration of 7.2 × 10^-4 M.What is the acid-ionization constant,K_a,for this acid?

• A)2.7 × 10^-2
• B)6.3 × 10^-3
• C)7.2 × 10^-4
• D)5.2 × 10^-6
• E)8.6 × 10^-5