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. $HCl$ $and$ $KCl$

The hydrogen ion concentration of a 10^-8 M HCl aqueous solution at 298 K (K_w = 10^-14) is:

1. \(1 . 0 \times \left(10\right)^{- 6}\) \(M\)

2. \(1 . 0525 \times \left(10\right)^{- 7}\) \(M\)

3. \(9 . 525 \times \left(10\right)^{- 8}\) \(M\)

4. \(1 . 0 \times \left(10\right)^{- 8}\) \(M\)

Which composition will make the basic buffer?

pH of a saturated solution of $\mathrm{Ca}{\left(\mathrm{OH}\right)}_2$ is 9. The solubility product $\left({\mathrm{K}}_{\mathrm{sp}}\right)$ of $\mathrm{Ca}{\left(\mathrm{OH}\right)}_2$ is:

1. $0.5\times {10}^{-10}$

2. $0.5\times {10}^{-15}$

3. $0.25\times {10}^{-10}$

4. $0.125\times {10}^{-15}$

1. H₃O⁺ and H₂F⁺, respectively.

2. OH^– and H₂F⁺, respectively.

3. H₃O⁺ and F^–, respectively.

4. OH^– and F^–, respectively.

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?
 

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. $HOCl{O}_3<HOCl{O}_2<HOClO<HOCl$

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

1. $H{S}^{-}$

2. $N{H}_2^{-}$

3. $F^{-}$

4. $l^{-}$

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