In the reaction H₂S+ H₂O₂ → S+ 2H₂O

• H₂S is an acid and H₂O₂ is a base

• H₂S is a base and H₂O₂ is an acid

• H₂S is an oxidising agent and H₂O₂ is a reducing agent

• H₂S is an reducing agent and H₂O₂ is a oxidising agent

The solubility product (Ks) of the following compounds are given at 25°C

Compounds	Ksp
AgCl	1.1 × 10-10
AgI	1.0 × 10-16
PbCrO4	4.0 × 10-14
Ag2CO3	8.0 × 10-12

The most soluble and least soluble compounds are

• AgCl and PbCrO₄

• AgI and Ag₂CO₃

• AgCl and Ag₂CO₅

• Ag₂CO₃ and AgI

Four moles of PCl₅ are heated in a closed 4 dm³ container to reach equilibrium at 400 K. At equilibrium 50% of PCl₅ is dissociated. What is the value of K_c for the dissociation of PCl₅ into PCl₃ and Cl₂ at 400 K?

• 0.50

• 1.00

• 1.25

• 0.05

154.

A weak monobasic acid is 1% ionized in 0.1 M solution at 25°C. The percentage of ionisation in its 0.025 M solution is

• 1

• 2

• 3

• 4

The aqueous solution of which of the salt has pH close to 7?

• FeCl₃

• CH₃COONa

• KCN

• CH₃COONH₄

Consider the following reactions in which all the reactants and the products are in gaseous state

  $$\begin{gathered} 2\mathrm{PQ} \rightleftharpoons {\mathrm{P}}_2 + {\mathrm{Q}}_2; {\mathrm{K}}_1 = 2.5 \times {10}^5 \\ \mathrm{PQ} + \frac{1}{2}{\mathrm{R}}_2 \rightleftharpoons \mathrm{PQR}: {\mathrm{K}}_2 = 5 \times {10}^{-3} \\ \mathrm{The} \mathrm{value} \mathrm{of} {\mathrm{K}}_3 \mathrm{for} \mathrm{the} \mathrm{equilibrium} \frac{1}{2}{\mathrm{P}}_2 +\frac{1}{2}{\mathrm{Q}}_2 +\frac{1}{2}{\mathrm{R}}_2 \rightleftharpoons \mathrm{PQR}, \mathrm{is} \end{gathered}$$

• 2.5 × 10^-3

• 2.5 × 10³

• 1.0 × 10^-5

• 5 × 10³

At a certain temperature, the dissociation constants of formic acid and acetic acid are 1.8 × 10^-4 and 1.8 × 10^-5 respectively. The concentration of acetic acid solution in which the hydrogen ion has the same concentration as in 0.001 M formic acid solution is equal to 

• 0.01 M

• 0.001 M

• 0.1 M

• 0.0001 M

What is the overall formation equilibriumconstant for the ion [ML₄]^2- ion, given that β₄ for this complex is 2.5 × 10¹³?

• 2.5 × 10¹³

• 5 × 10^-13

• 2.5 × 10^-14

• 4.0 × 10^-13

1.6 moles of PCl₅(g) is placed in 4 dm closed vessel. When the temperature is raised to 500 K, it decomposes and at equilibrium 1.2 moles of PCl₅(g) remains. What is the K, value for the decomposition of PCl₅(g) to PCl₃(g) and Cl₅(g) at 500 K?

• 0.013

• 0.050

• 0.033

• 0.067

For a concentrated solution of a weak electrolyte A_xB_y of concentration 'C', the degree of dissociation 'a' is given as

• α = √ K_eq/ C ( x + y)

• α = √ K_eq/ C ( xy)

• α =( K_eq/ Cxy)

• α =( K_eq/ C^xy)