1. | Weak acid and it's salt with a strong base. |
2. | Equal volumes of equimolar solutions of weak acid and weak base. |
3. | Strong acid and its salt with a strong base. |
4. | Strong acid and its salt with a weak base. (The pKa of acid = pKb of the base) |
Which composition will make the basic buffer?
1. | 100 mL of 0.1 M HCl+100 mL of 0.1 M NaOH |
2. | 50 mL of 0.1 M NaOH+25 mL of 0.1 M CH3COOH |
3. | 100 mL of 0.1 M CH3COOH+100 mL of 0.1 M NaOH |
4. | 100 mL of 0.1 M HCl+200 mL of 0.1 M NH4OH |
An acidic buffer cannot be formed by which of the following combinations is:
1.
2.
3.
4.
Buffer solutions have constant acidity and alkalinity because:
1. | these give unionized acid or base on reaction with added acid or alkali. |
2. | acid and alkali in these solutions are shielded from attack by other ions |
3. | they have large excess of H+ or OH- ions |
4. | they have fixed value of pH |
A buffer solution is prepared in which the concentration of NH3 is 0.30 M and the concentration of is 0.20 M. If the equilibrium constant, Kb for NH3 equals 1.8×10–5, then what is the pH of this solution?
(log 1.8 = 0.25; log 0.67 = –0.176)
1. 9.43
2. 11.72
3. 8.73
4. 9.08
What is [H+] in mol/L of a solution that is 0.20 M in CH3COONa and 0.10 M in CH3COOH ?(Ka for CH3COOH = 1.8 x 10-5):
1.
2.
3.
4.
In a buffer solution containing an equal concentration of B- and HB, the Kb for B- is 10-10. pH of the buffer solution is:
1. | 10 | 2. | 7 |
3. | 6 | 4. | 4 |
The following pair constitutes a buffer is:
1.
2.
3.
4.
The rapid change of pH near the stoichiometric point of an acid-base titration is the basis of indicator detection. pH of the solution is related to the ratio of the concentrations of the conjugate acid (HIn) and base (In–) forms of the indicator by the expression:
1.
2.
3.
4. All of the above.