1) A 0.029 M solution of a weak acid (HA) has a pH of 4.33. What is the K_a of the acid?

 

 

2)Nitrous acid, HNO₂, has a K_a of 7.1×10⁻⁴. 

What are

[H₃O⁺]

,[NO₂⁻]

, and [OH⁻] in 0.56 MHNO₂?

 

 

3)Hydrofluoric acid, HF, has a K_a of 6.8×10⁻⁴. 

What are

[H₃O⁺]

,[F⁻], 

and [OH⁻] in 0.910 M HF?

 

 

4)Chloroacetic acid, ClCH₂COOH, has a pK_a of 2.87. 

What are

[H₃O⁺], 

pH,

[ClCH₂COO⁻], 

and [ClCH₂COOH] in 2.45 M ClCH₂COOH?

 

5)In a 0.75 M solution, a weak acid is 1.8% dissociated.
 
(a) What are

[H₃O⁺], 

pH,

[OH⁻]

, and pOH of the solution.

 

(b)  What is Ka of the acid?

 

6)A 0.355−mol sample of HX is dissolved in enough H₂O to form 815.0 mL of solution. If the pH of the solution is 3.10, what is the K_a of HX? 

 

7) The weak acid HZ has a K_a of 2.55×10⁻⁴. Calculate the pH of 0.080 M HZ.

pH= ?

 

8) Acetylsalicylic acid (aspirin),HC₉H₇O₄,is the most widely used pain reliever and fever reducer. Find the pH of 0.021 Maqueous aspirin at body temperature (K_a at 37° = C = 3.6× 10⁻⁴.)

pH=?

 

9)The weak acid HQ has a pK_a of 4.89. Calculate the

[H₃O⁺] of 0.065 M HQ.
 
[H₃O⁺]=?

 

10) Farmers who raise cotton once used arsenic acid, H₃AsO₄, as a defoliant at harvest time. Arsenic acid is a polyprotic acid with K₁ = 2.5 × 10⁻⁴, K₂ = 5.6 × 10⁻⁸, and K₃ = 3 × 10⁻¹³. What is the pH of a 0.500 M solution of arsenic acid?