Acid bases and pH

In the Bronsted-Lowry definition of acids and bases, an acid is

• A prton acceptor

• A proton donor

• corrodes metals

• Forms hydrogen ions in water

In the bronsted-lowry definition of acids and bases, a base

• forms hroxide ions

• is a proton acceptor

• is a proton donor

• forms hydrogen bonds

In the following reaction in aqueous solution the acid is......... and the conjugate base is.......

• 
• 
• 
• 

Which of the following is the conjugate acid of the hydrogen phosphate ion HPO₄^2-

• H₂PO₄^-

• H₃O⁺

• H₂PO₄^2-

• H₃PO₄

Which of the following a strong acid

• HNO₂

• H₂S

• H₂SO₃

• HF

Solutions of each of the hypothetical acids in the following table are prepared with an initial concentration of 0.100 M.

Which of the four solutions will have the lowest pH and be most acidic?

• HA

• HB

• HC

• HD

A 0.040 mol dm^–3 solution of a weak monobasic acid is 1.0% dissociated.What is the value of K_a for the acid?

• 2.0 × 10^–7 mol dm^–3

• 4.0 × 10^–6 mol dm^–3

• 4.0 × 10^–4 mol dm^–3

• 4.0 × 10^–2 mol dm^–3

HA and HB are two strong monobasic acids. 25.0 cm³ of 6.0 mol dm⁻³   

HA is mixed with 45.0 cm³ of 3.0 mol dm⁻³  HB. What is the H⁺(aq) concentration, in mol dm⁻³, in the resulting solution?

• 1.9

• 2.1

• 4.1

• 4.5

The equation shows the dissociation of the acid H₃AsO₄ in water.

H₃AsO₄ + H₂O ⇌ H₂AsO₄^– + H₃O⁺

Which pair is a conjugate acid–base pair?

• H₃AsO₄ and H₂O

• H₂AsO₄^– and H₃O⁺

• H₃AsO₄ and H₃O⁺

• H₃O⁺ and H₂O

20 cm³ of 0.10 mol dm^–3 hydrochloric acid is added to 10 cm³ of 0.10 mol dm^–3 sodium hydroxide. What is the pH of the resulting mixture?

• 1.00

• 1.18

• 1.30

• 1.48