The conjugate base of \(H_2PO_{4}^{-}\) is:

1. \(PO_{4}^{3-}\)

2. \(P_2O_5\)

3. \(H_3PO_4\)

4. \(HPO_{4}^{2-}\)

The equilibrium constant for the reaction
\(\mathrm{N}_{2}(g)+\mathrm{O}_{2}(g) \rightleftharpoons 2 \mathrm{NO}(g)\)
at temperature T is \(4 \times 10^{-4}\) . The value of K_c for the reaction,
\(\mathrm{{NO}}(g) \rightleftharpoons \frac{1}{2} \mathrm{{~N}_{2}}(g)+\frac{1}{2} \mathrm{O}_{2}(g)\)at the same temperature) is:

Solubility of Ca(OH)₂ is s mol L^-1 . The solubility product (K_sp) under the same condition is : 

1. 4s³ 

2. 3s⁴

3. 4s² 

4. s³

The species, among the following, that act as both Brönsted acid and base is/are:

1. \(H_2PO^-_2 \) 

2.  \(HPO^{2-}_3\)

3. \(HPO^{2-}_4\)

4. All of the above

An aqueous solution of 1M NaCl and 1M HCl is : 

1. not a buffer but pH < 7 

2. not a buffer but pH >7 

3. a buffer with pH <7 

4. a buffer with pH >7 

For the following reaction in gaseous phase \(\mathrm{CO}+\frac{1}{2} \mathrm{O}_{2} \longrightarrow \mathrm{CO}_{2} ; \quad \dfrac {K_{c}}{K_{p}} \text { is : }\)

One of the following equilibria is not affected by change in volume of the flask. The correct option is: 

\(1. \mathrm{PCl}_{5}(g) \rightleftharpoons \mathrm{PCl}_{3}(g)+\mathrm{Cl}_{2}(g)\\ 2. \mathrm{N}_{2}(g)+3 \mathrm{H}_{2}(g) \rightleftharpoons 2 \mathrm{NH}_{3}(g)\\ 3. \mathrm{N}_{2}(g)+\mathrm{O}_{2}(g) \rightleftharpoons 2 \mathrm{NO}(g)\\ 4. \mathrm{SO}_{2} \mathrm{Cl}_{2}(g) \rightleftharpoons \mathrm{SO}_{2}(g)+\mathrm{Cl}_{2}(g)\)

pH of 0.005M calcium acetate (pk_a of CH₃COOH = 4.74) is: 

In a closed reaction vessel, Phosphorus pentachloride dissociates as follows:

\(\mathrm{PCl}_{5}(g) \rightleftharpoons \mathrm{PCl}_{3}(g)+\mathrm{Cl}_{2}(g)\)

If the total pressure at equilibrium of the reaction mixture is P and the degree of dissociation of PCl₅  is x, the partial pressure of PCl₃ will be:

1. \(\left(\frac{x}{x+1}\right) P\)

2. \(\left(\frac{2x}{x-1}\right) P\)

3. \(\left(\frac{x}{x-1}\right) P\)

4.  \(\left(\frac{x}{1-x}\right) P\)

An amount of solid NH₄HS is placed in a flask already containing ammonia gas at a certain temperature and 0.50 atm pressure. Ammonium hydrogen sulphide decomposes to yield NH₃ and H₂S gases in the flask. When the decomposition reaction reaches equilibrium, the total pressure in the flask rises to 0.84 atm? The equilibrium constant for NH₄HS decomposition at this temperature is:

1. 0.11

2. 0.17

3. 0.18

4. 0.30