21.

The correct structure of tribromooctaoxide is

• 

• 

• 

• 

For a cell involving one electron E°_cell = 0.59 V at 298 K, the equilibrium constant for the cell reaction is :[ Given that $\frac{2.303}{\mathrm{F}}= 0.059\mathrm{V} \mathrm{at} \mathrm{T} = 298 \mathrm{K}]$.

• 1.0 × 10⁵

• 1.0 × 10¹⁰

• 1.0 × 10³⁰

• 1.0 × 10²

The number of moles of hydrogen molecules required to produce 20 moles of ammonia through Haber's process is :

• 20

• 30

• 40

• 10

Which is the correct thermal stability order for H₂E (E = O, S, Se, Te and Po)?

• H₂O < H₂S < H₂Se < H₂Te < H₂Po

• H₂Po < H₂Te < H₂Se < H₂S < H₂S

• H₂Se < H₂Te <H₂Po < H₂O < H₂S

• H₂S < H₂O < H₂Se < H₂Te <H₂Po

Identify the incorrect statement related to PCl₅ from the following:

• Two axial P–Cl bonds make an angle of 180° with each other

• Axial P–Cl bonds are longer than equatorial P–Cl bonds

• PCl₅ molecules in non-reactive

• Three equatorial P–Cl bonds make an angle of 120° with each other

Which one is malachite from the following?

• Cu(OH)₂

• Fe₃O₄

• CuCO₃.Cu(OH)₂

• CuFeS₂

The mixture that forms maximum boiling azeotrope is:

• Ethanol + Water

• Acetone + Carbon disulphide

• Heptane + Octane

• Water + Nitric acid

For an ideal solution, the correct option is :

• Δ_mix V ≠  0 at constant T and P

• Δ_mix H =  0 at constant T and P

• Δ_mix G =  0 at constant T and P

• Δ_mix S = 0 at constant T and P

If the rate constant for a first order reaction is k, the time (t) required for the completion of 99% of the reaction is given by:

• t = 6.909/k

• t = 4.606/k

• t = 2.303/k

• t = 0.693/k

For the cell reaction

2Fe³⁺ (aq) +2l^-(aq) → 2Fe²⁺(aq) + I₂(aq)

E${}_{\mathrm{cell}}^{⊝}$= 0.24V at 298 K. The standard Gibbs energy (Δ_rG^Θ) of the cell reaction is:

[Given that Faraday constant F = 96500 C mol^–1]

• – 23.16 kJ mol^–1

• 46.32 kJ mol^-1

• 23.16 kJ mol^-1

• - 46.32 kJ mol^-1