Calculate the pH of i) 0.300 M and ii) 0.030 M HNO₂ solution. In which case do you have to use the quadratic formula? The K_a of HNO₂ is 4.0 × 10^–4.

Phenypropanoic acid (C₉H₁₀O₂) is a white, crystalline solid with a sweet floral smell widely used in cosmetics and food flavorings. It is a weak monoprotic base with K_a value of 2.2×10^–5. If 750 mg of C₉H₁₀O₂ is dissolved in 500.0 mL of water, calculate the pH of the solution and the percent ionization.

The pH for a 0.75 M acid solution is 4.67. Determine the K_a for the acid.

Boric acid has a pK_a of 9.27. What is the pH of a 0.045 M solution of boric acid?

HBrO has an acid-dissociation constant of 2.800×10⁻⁹. If the initial concentration of HBrO is 0.01750 M, what are the concentrations of H₃O⁺, BrO⁻, and HBrO at equilibrium?

What is the pH of 0.450 M H HF solution? Can we apply the assumption that x is small?

The Ka value for formic acid is 1.8×10⁻⁴. It has a density of 1.22 g/mL.

HCOOH (aq) + H₂O(l) ⇌ HCOO^-(aq) + H₃O⁺ (aq)

Calculate the concentration of formate ions in the solution made by 25.0 mL of formic acid diluted to a final volume of 300.0 mL in water. Express the answer with two significant figures.