In a buffer solution containing an equal concentration of B^- and HB, the K_b for B^- is 10^-10. pH of the buffer solution is:

1.	10	2.	7
3.	6	4.	4

Which of the following molecular hydrides acts as a Lewis acid?

1. $N{H}_3$

2. $H_{2}O$

3. $B_2{H}_6$

4. $C{H}_4$

The tendency of BF₃, BCl₃ and BBr₃ to behave as Lewis acid decreases in the sequence:

1. $BC{l}_3>B{F}_3>BB{r}_3$

2. $BB{r}_3>BC{l}_3>B{F}_3$

3. $BB{r}_3>B{F}_3>BC{l}_3$

4. $B{F}_3>BC{l}_3>BB{r}_3$

The ionization constant of ammonium hydroxide is 1.77 x 10^-5 at 298 K. Hydrolysis constant of ammonium Chloride is:

1. 5.65 x 10^-10

2. 6.50 x 10^-12

3. 5.65 x 10^-13

4. 5.65 x 10^-12

What is the [OH^-] in the final solution prepared by mixing 20.0 mL of 0.050 M HCl with 30.0 mL of 0.10 M Ba(OH)₂?

1. 0.10 M

2. 0.40 M

3. 0.0050 M

4. 0.12 M

The dissociation constants for acetic acid and HCN at 25 °C are 1.5 x 10^-5 and 4.5 x 10^-10, respectively. The equilibrium constant for the equilibrium, 
CN^- + CH₃COOH  ⇌  HCN + CH₃COO^- 
would be:
1. $3.0\times {10}^5$
2. $3.0\times {10}^{-5}$
3. $3.0\times {10}^{-4}$
4. $3.0\times {10}^4$

Equal volumes of three acid solutions of pH 3, 4 and 5 are mixed in a vessel. What will be the H⁺ ion concentration in the mixture?
1. $1.11\times {10}^{-4}$ $\mathrm{M}$
2. $3.7\times {10}^{-4}$ $\mathrm{M}$
3. $3.7\times {10}^{-3}$ $\mathrm{M}$
4. $1.11\times {10}^{-3}$ $\mathrm{M}$

If the concentration of OH ' ions in the reaction