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. $1.11\times {10}^{-3}$ $\mathrm{M}$

The value of the equilibrium constant of the reaction 
 $\mathrm{HI}\left(\mathrm{g}\right)$ $\leftrightharpoons$ $\frac{1}{2}{\mathrm{H}}_2\left(\mathrm{g}\right)$ $+$ $\frac{1}{2}{\mathrm{I}}_2$ is 8.0.
The equilibrium constant of the reaction
 ${\mathrm{H}}_2\left(\mathrm{g}\right)$ $+$ ${\mathrm{I}}_2\left(\mathrm{g}\right)$ $\leftrightharpoons$ $2\mathrm{HI}\left(\mathrm{g}\right)\hspace{0.17em}$ will be-

The pOH of a solution at 25 °C that contains 1×10^-10 M of hydronium ions is:

The following equilibrium constants are given: 
N₂ + 3H₂ ⇌ 2NH₃; K₁ 
N₂ + O₂ ⇌ 2NO; K₂ 
H₂ + 1/2O₂ ⇌ H₂O; K₃ 

The equilibrium constant for the oxidation of NH₃ by oxygen to give NO is:

1. $K_2{K}_3^3/K_1$

2. $K_2{K}_3^2/K_1$

3. $K_2^2{K}_3/K_1$

4. $K_1{K}_2/K_3$ 

The ionic species that has the greatest proton affinity to form stable compound is:

1. $H{S}^{-}$

2. $N{H}_2^{-}$

3. $F^{-}$

4. $l^{-}$

Which one of the following orders correctly represents the increasing acid strengths of the given acids?

1. $HOCl<HOClO<HOCl{O}_2<HOCl{O}_3$

2. $HOClO<HOCl<HOCl{O}_3<HOCl{O}_2$

3. $HOCl{O}_2<HOCl{O}_3<HOClO<HOCl$

4. $HOCl{O}_3<HOCl{O}_2<HOClO<HOCl$

For the reaction, 
CH₄(g) + 2O₂(g) CO₂(g) + 2H₂O(l) 
Δ_rH = -170.8 kJ mol^-1 
Which of the following statements is not true?
 

The following pair constitutes a buffer is:

1. $HN{O}_2$ $and$ $NaN{O}_2$

2. $NaOH$ $and$ $NaCl$

3. $HN{O}_3$ $and$ $N{H}_{4}N{O}_3$

4. $HCl$ $and$ $KCl$