The dissociation constants for acetic acid and HCN at 25$°$C are 1.5 xl0^-5 and 4.5 xl0^-10,

respectively. The equilibrium constant for the equilibrium,

CN^- + CH₃COOH  =    HCN + CH₃COO^-   would be

1. 3.0 x 10⁵

2. 3.0 x 10^-5

3. 3.0x10^-4

4. 3.0 x 10⁴

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 x 10^-4 M             

2. 3.7 x 10^-4 M

3. 3.7 x 10^-3  M             

4. 1.11 x 10^-3 M

The dissociation equilibrium of a gas AB₂ can be represented as

$2{\mathrm{AB}}_2\left(\mathrm{g}\right) \stackrel{ }{\rightleftharpoons }2\mathrm{AB}\left(\mathrm{g}\right) +\hspace{0.17em}{\mathrm{B}}_2\left(\mathrm{g}\right)$

The degree of dissociation is 'x' and is small compared to 1. The expression relating the degree of dissociation (x) with equilibrium constant K_p and total pressure p is

(1) (2k_p/p)

(2) (2K_p/p)^1/3

(3) (2K_p/p)^1/2

(4) (K_p/p)

The value of equilibrium constant of the reaction HI (g) $\rightleftharpoons$ $\frac{1}{2}$ H₂(g) + $\frac{1}{2}$ I₂(g) is 8.0. The equilibrium constant of the reaction

H₂(g) + I₂(g) $\rightleftharpoons$2HI(g) will be

$$\begin{gathered} 1. \frac{1}{16} \\ 2. \frac{1}{64} \\ 3. 16 \\ 4. \frac{1}{8} \end{gathered}$$

Which one of the following ionic species has the greatest proton affinity to form stable compound?

(1) HS^-                         

(2) ${\mathrm{NH}}_2^{-}$

(3) F^-                           

(4) I^-

Given the reaction:

\(\mathrm{Cu}(\mathrm{~s})+2 \mathrm{Ag}^{+}(\mathrm{aq}) \rightarrow \mathrm{Cu}^{2+}(\mathrm{aq})+2 \mathrm{Ag}(\mathrm{~s})\) with E° = 0.46 V at 298 K,
what is the equilibrium constant for the reaction?

For the reaction,

 CH₄(g) + 2O₂(g) $\rightleftharpoons$CO₂(g) + 2H₂O (l),

 $∆$_rH = -170.kJ mol-1

Which of the following statements is not true?

(a) At equilibrium, the concentrations of CO₂(g) and H₂O(l) are not equal

(b) The equilibrium constant for the reaction is given by K_p = [CO₂]/[CH₄][O₂]

(c) Addition of CH₄(g) or O₂ (g) at equilibrium will cause a shift to the right

(d) The reaction is exothermic

Which of the following pairs constitutes a buffer?

1. HNO₂ and NaNO₂

2. NaOH and NaCl

3. HNO₃ and NH₄NO₃

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) 1.0×10^-6 M

(2) 1.0525 x 10^-7 M

(3) 9.525 x 10^-8 M

(4) 1.0×10^-8 M

Two flasks A and B of equal volume containing 1 mole and 2 mole of O₃ respectively, are heated to the sametemperature. When the reaction 2O₃ $\underset{}{\overset{}{\leftrightharpoons }}$3O₂ practically stops, then both the flasks shall have

(1) the same ratio [O₂] /[O₃]

(2) the same ratio : [O₂]³/²/[O₃]

(3) only O₂

(4) the same time to reach equilibrium