31.

The velocity constant for a reaction is 0.693 × 10^-1 min^-1 and intial concentration is 0.2 mol/L, the half-life periods is

• 400s

• 600s

• 800s

• 100s

For the chemical reaction N₂ + 3H₂ → 2NH₃, if $\frac{\mathrm{d}\left[{\mathrm{NH}}_3\right]}{\mathrm{dt}} = 2\times {10}^{-4} \mathrm{mol} {\mathrm{L}}^{-1} {\mathrm{s}}^{-1}, \mathrm{the}\hspace{0.17em}\mathrm{value}\hspace{0.17em}\mathrm{of}\hspace{0.17em}\frac{-\mathrm{d}\left[{\mathrm{H}}_2\right]}{\mathrm{dt}} \mathrm{is}$

•  1 × 10^-4 mol L^-1 s^-1

• 3 × 10^-4 mol L^-1 s^-1

• 4 × 10^-4 mol L^-1 s^-1

• 6 × 10^-4 mol L^-1 s^-1

E°= -0.44V for the reaction, Fe²⁺ + 2e^- → Fe and E°= -0.76 V for the reaction, Zn²⁺ + 2e^- → Zn. Which of the following statement is correct?

• Fe is more electropositive

• Zn is more electropositive

• Zn is more electronegative

• None of the above

For the electrolysis of aqua CuSO₄ solution using inert Pt electrodes, the reaction on anode

• $2{\mathrm{SO}}_4^{2-} \to {\mathrm{S}}_2{\mathrm{O}}_3^{2-} + 2\frac{1}{2}{\mathrm{O}}_2 + 2{\mathrm{e}}^{-}$

• Cu²⁺ + 2e^- → Cu

• 2H₂O  → O₂ + 4H⁺+ 4e^-

• 2H⁺ + 2e^- → H₂

Which of the following chemical reactions is homogeneous catalytic reaction?

• N₂(g) + 3H₂(g) $\stackrel{\mathrm{Fe}}{\to }$ 2NH₃(g)

• 2SO₂(g) + O₂(g) $\stackrel{\mathrm{NO}}{\to }$ 2SO₃ (g)

• CO(g) + 3H₂(g) _{$\stackrel{\mathrm{Ni}}{\to }$} CH₄(g) + H₂O (g)

• 2SO₂(g) + O₂(g) $\stackrel{{\mathrm{V}}_2{\mathrm{O}}_5}{\to } 2{\mathrm{SO}}_3\left(\mathrm{g}\right)$

In which of the following compound the oxidation number of oxygen is +2?

• H₂O₂

• CO₂

• H₂O

• OF₂

[(C₆H₅)₂Pd(NCS)₂] and [(C₆H₅)₂Pd(SCN)₂] are

• bond isomeric

• coordinated isomeric

• ionic isomeric

• geometrical isomeric

In which of the following complex compounds the oxidation number of the metal is zero?

• [Pt(NH₃)₂Cl₂]

• [Cr(CO)₆]

• [Cr(NH₃)₃Cl₃]

• [Cr(en)₂Cl₂]

Transitional elements are mostly

• diamagnetic

• paramagnetic

• neither diamagnaetic nor paramagnetic

• diamagentic and paramagnetic both

In which of the following compounds carboxylic group (-COOH) is not present?

• Acetic acid

• Lactic acid

• Benzoic acid

• Picric acid