An acidic buffer cannot be formed by which of the following combinations is:

1. ${\mathrm{HClO}}_4$ $\mathrm{and}$ ${\mathrm{NaClO}}_4$
2. ${\mathrm{CH}}_3\mathrm{COOH}$ $\mathrm{and}$ ${\mathrm{CH}}_3\mathrm{COONa}$
3. ${\mathrm{H}}_2{\mathrm{CO}}_3$ $\mathrm{and}$ ${\mathrm{Na}}_2{\mathrm{CO}}_3$
4. ${\mathrm{H}}_3{\mathrm{PO}}_4$ $\mathrm{and}$ ${\mathrm{Na}}_3{\mathrm{PO}}_4$

If the equilibrium constant for N₂(g) + O₂ (g) ⇄ 2NO(g) is K, the equilibrium constant for \(\frac{1}{2}\)N₂(g) + \(\frac{1}{2}\)O₂(g) ⇄ NO(g) will be?

1. $K^{\frac{1}{2}}$

2. $\frac{1}{2}K$

3. K

4. $K^2$

The value of the equilibrium constant for a particular reaction is 1.6 × 10¹². When the system is in equilibrium, it will include:
1. All reactants
2. Mostly reactants
3. Mostly products
4. Similar amounts of reactants and products

The K_sp of Ag₂CrO₄, AgCl, AgBr, and Agl are respectively, 1.1 × 10^–12, 1.8 × 10^–10, 5.0 × 10^–13, 8.3 × 10^–17. Which one of the following salts will precipitate last if ${\mathrm{AgNO}}_3$ solution is added to the solution containing equal moles of NaCl, NaBr, Nal, and Na₂CrO₄?

1. Agl

2. AgCl

3. AgBr

4. Ag₂CrO₄

For the reversible reaction:
N₂(g) + 3H₂(g) \(\rightleftharpoons\) 2NH₃(g) + heat 

The equilibrium shifts in a forward direction:

1. by increasing the concentration of $N{H}_3\left(g\right)$
2. by decreasing the pressure.
3. by decreasing the concentration of $N_2\left(g\right)$ $and$ $H_2\left(g\right)$
4. by increasing pressure and decreasing temperature.

Buffer solutions have constant acidity and alkalinity because:
 

A buffer solution is prepared in which the concentration of NH₃ is 0.30 M and the concentration of  $N{H}_4^{+ }$ is 0.20 M. If the equilibrium constant, K_b 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

The value of $∆\mathrm{H}$ for the reaction is less than zero. Formation of $X_2\left(g\right)$ $+$ $4$ $Y_2\left(g\right)$ $\leftrightharpoons 2X{Y}_4\left(g\right)$ will be favoured at:

For the reaction ${\mathrm{N}}_2\left(\mathrm{g}\right)$ $+$ ${\mathrm{O}}_2\left(\mathrm{g}\right)\leftrightharpoons 2\mathrm{NO}\left(\mathrm{g}\right)$ the equilibrium constant is K₁. The equilibrium constant is K₂ for the reaction  $2\mathrm{NO}\left(\mathrm{g}\right)$ $+$ ${\mathrm{O}}_2\left(\mathrm{g}\right)$ $\leftrightharpoons 2{\mathrm{NO}}_2\left(\mathrm{g}\right)$ $$
The value of K for the reaction given below will be:
${\mathrm{NO}}_2\left(\mathrm{g}\right)\leftrightharpoons \frac{1}{2}{\mathrm{N}}_2\left(\mathrm{g}\right)$ $+{\mathrm{O}}_2\left(\mathrm{g}\right)$ $$

1.  $\frac{1}{4}$ $\left(4\right)$ ${\mathrm{K}}_1$ ${\mathrm{K}}_2$

2.  ${\left[\frac{1}{{\mathrm{K}}_1{\mathrm{K}}_2}\right]}^{1/2}$

3.  $\frac{1}{\left({\mathrm{K}}_1{\mathrm{K}}_2\right)}$

4.  $\frac{1}{\left(2{\mathrm{K}}_1{\mathrm{K}}_2\right)}$

What is [H⁺] in mol/L of a solution that is 0.20 M in CH₃COONa and 0.10 M in CH₃COOH ?(K_a  for CH₃COOH = 1.8 x 10^-5):
1. \(3 . 5 \times \left(10\right)^{- 4}\)
2. \(1 . 1 \times \left(10\right)^{- 5}\)
3. \(1 . 8 \times \left(10\right)^{- 5}\)
4. \(9 . 0 \times \left(10\right)^{- 6}\)${\mathrm{}}^{}$