For the given reaction: 

PCl_{5 (g)}  $\leftrightharpoons$PCl_{3 (g)} + Cl_{2 (g)}, ∆_rH° = 124.0 kJ mol^–1 and K_c = 8.3 $\times$ 10^-3 mol L^-1 at 473 K

The effect on K_c if (i) pressure is increased  and (ii) the temperature is increased will be, respectively-

1. (i) Will increase; (ii) will decrease

2. (i) Will decrease; (ii) will remain the same 

3. (i) Will remain the same; (ii) will increase

4. (i) will remain the same; (ii) Will decrease

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

1. ${\mathrm{HSO}}_4^{-}$, ${\mathrm{CO}}_3^{2-}$

2.  HSO₄^-, CO₃^-

3. SO₄^-2, CO₃^2-

4. HS₂O₄^-, CO₃^2-

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

1. N₂H₆, NH⁴⁺, HCOOH

2. NH₃, ${\mathrm{NH}}_4^{+}$ , HCOOH

3. NH₃, NH⁴⁺, HCOO₃

4. N₂H, NH⁴⁺, HCOOH

OH^– , F^– , H⁺ and BCl₃

The ionization constants of HCOOH, and HCN at 298K are 1.8 × 10^–4 and 4.8 × 10^–9 respectively. The ionization constants of the corresponding conjugate bases of HCOOH and HCN will be

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

(a) Human muscle-fluid,  pH = 6.83 

(b) Human stomach fluid, pH = 1.2

(c) Human blood, pH = 7.38           

(d) Human saliva, pH = 6.4.