Question

I need help with problems from a practice exam involving acids and bases

QUESTION 1

1. Complete the following equation:     (CH₃)₃N + H₂O -->

   		(CH3)3NH+ + –OH
   		(CH3)3NH+ + H3O+
   		(CH2)3N + H3O+
   		H(CH3)3N + –OH
   		No reaction

1 points   

QUESTION 2

1. The pH of a 0.500 M solution of an unknown acid (HA) is 6.45 at 25 ⁰C. Determine the value of the equilibrium constant for this acid at 25 ⁰C.

   		3.55 x 10–7
   		2.82 x 10–8
   		2.52 x 10–13
   		1.59 x 10–15
   		None of the above

1 points   

QUESTION 3

1. What is the pH of 0.20 M C₆H₅COOH? (K_a[C₆H₅COOH = 6.46 x 10^–5])

   		0.70
   		2.44
   		4.60
   		11.56
   		13.30
   		None of the above

1 points   

QUESTION 4

1. What is the pH of a 0.350 M solution of triethylamine [(CH₃CH₂)₃N]? [K_b = 5.2 X 10^─4]. Assume that you can neglect x.

   		0.46
   		1.87
   		10.26
   		12.13
   		None of the above

1 points   

QUESTION 5

1. When calculating pH for 0.10 M CH₃COOH, which of the following is true?

   		[CH3COOH]init = [H3O+]equil
   		[CH3COOH]init ≠ [H3O+]equil
   		The –log of 0.10 M is pOH, since CH3COOH is not a strong acid.
   		A Ka value is required.
   		Both b and d.
   		Both b and c.

Answer 1

ques 5. Both b and c is correct option.weak acid doesnot disscociate compeletly