Given an endothermic reaction:

CH_{4 (g)} + H₂O _(g)  $\leftrightharpoons \hspace{0.17em}$CO _(g) + 3H_{2 (g)}

If the temperature is increased, then:

1. The equilibrium will not be disturbed.

2. The equilibrium will shift in the backward direction.

3. The equilibrium will shift in the forward direction.

4. None of the above.

Find the effect of (i) increasing pressure and (ii) increasing temperature on Kc for the following equilibrium:

PCl₅(g) ⇌ PCl₃(g) + Cl₂(g)

ΔᵣH° = +124.0 kJ mol⁻¹
Kc = 8.3 × 10⁻³ mol L⁻¹ at 473 K

The conjugate acid-base pair is:

1. A pair that differs only by one proton

2. A pair that differs only by the size

3. A pair that differs only by electronegativity

4. None of the above

The conjugate acids for the Brönsted bases  ${\mathrm{NH}}_2^{-}$ , NH₃ and HCOO^– will be respectively:

1. N₂H₆, ${\mathrm{NH}}_4^{+}$ HCOOH

2. NH₃, ${\mathrm{NH}}_4^{+}$ , HCOOH

3. NH₃, ${\mathrm{NH}}_4^{+}$, HCOO₃

4. N₂H, ${\mathrm{NH}}_4^{+}$, HCOOH

The species described below that contain Lewis acids are:

OH^– , F^– , H⁺ and BCl₃

The ionization constants of formic acid (HCOOH) and hydrocyanic acid (HCN) at 298 K are 1.8 × 10⁻⁴ and 4.8 × 10⁻⁹, respectively. What are the ionization constants of their corresponding conjugate bases, HCOO⁻ and CN⁻, under the same conditions?

The ionization constant of phenol is 1.0 × 10^–10. The concentration of phenolate ion in 0.05 M solution of phenol will be:

The first ionization constant of H₂S is 9.1 × 10^–8. The concentration of HS^– ion in its 0.1 M solution will be:

The ionization constant of acetic acid is \(1.74 × 10^{–5}.\) The pH of acetic acid in its 0.05 M solution will be:
1. 7.81