Which of these is least likely to act as Lewis base?
1. F^–
2. BF₃
3. PF₃
4. CO

The strongest acid among the following compounds is:

pH of a saturated solution of Ba(OH)₂ is 12. The value of solubility product K_sp of Ba (OH)₂ is:
1. $3.3\times {10}^{-7}$
2. $5.0\times {10}^{-7}$
3. $4.0\times {10}^{-6}$
4. $5.0\times {10}^{-6}$

Equimolar solutions of the following substances were prepared separately. Which one of these will record the highest pH value?
1. $BaC{l}_2$
2. $AlC{l}_3$
3. $LiCl$
4. $BeC{l}_2$

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. $3.5\times {10}^{-4}$
2. $1.1\times {10}^{-5}$
3. $1.8\times {10}^{-5}$
4. $9.0\times {10}^{-6}$

The equilibrium reaction that doesn't have equal values for K_c and K_p is: 

1. \(2NO(g) \rightleftharpoons N_2(g) + O_2(g)\)
2. \(SO_2(g) + NO_2(g) \rightleftharpoons SO_3(g) + NO(g)\)
3. \(H_2(g) + I_2(g) \rightleftharpoons 2HI (g)\)
4. \(2C(s) + O_2(g) \rightleftharpoons 2CO_2(g)\)