Which of the following is not a Lewis base ?

• NH₃

• H₂O

• AlCl₃

• None of these

The solubility in water of a sparingly soluble salt AB₂ is 1.0 × 10^-5 mol L^-1. Its solubility product number will be

• 4 × 10^-15

• 4 × 10^-10

• 1 × 10^-15

• 1 × 10^-10

The correct order of increasing basic nature for the bases NH₃, CH₃NH₂ and (CH₃)₂NH is

• CH₃NH₂ < NH₃ < (CH₃)₂NH

• (CH₃)₂NH < NH₃ < CH₃NH₂

• NH₃ < CH₃NH₂ < (CH₃)₂NH

• CH₃NH₂ < (CH₃)₂NH < NH₃

The solubility of CaF₂ in pure water is 2.3 ×10^-6 mol dm^-3. Its solubility product will be:

• 4.8 ×10^-18

• 48.66 ×10^-18

• 4.9 ×10^-11

• 48.66 ×10^-15

Two moles of PCl₅ were heated in a closed vessel of 2 L. At equilibrium 40% of PCl₅ is  dissociated into PCl₃ and Cl₂.The,value of equilibrium constant is :

• 0.53

• 0.267

• 2.63

• 5.3

What is the equilibrium expression for the reaction

P₄ (s) + 5O₂ (g) $\rightleftharpoons$ P₄O₁₀ (s) ?

• K_c = $\frac{\left[{\mathrm{P}}_4{\mathrm{O}}_{10}\right]}{\left[{\mathrm{P}}_4\right][{\mathrm{O}}_2{]}^5}$

• K_c = $\frac{\left[{\mathrm{P}}_4{\mathrm{O}}_{10}\right]}{5\left[{\mathrm{P}}_4\right]\left[{\mathrm{O}}_2\right]}$

• K_c = [O₂]⁵

• K_c = $\frac{1}{[{\mathrm{O}}_2{]}^5}$

The pH value of 1/1000 N-KOH solution is :

• 3

• 10^-11

• 2

• 11

378.

The temperature dependence of rate constant (k) of a chemical reaction is written in terms of Arrhenius equation, k = Ae^{-E*/ RT}. Activation energy (E*) of the reaction can be calculated by plating

• log k vs $\frac{1}{\mathrm{T}}$

• log k vs $\frac{1}{\log \mathrm{T}}$

• k vs T

• k vs $\frac{1}{\log \mathrm{T}}$

The heats of combustion of carbon monoxide at constant pressure and at constant volume at 27°C will differ from one another by :

• 27 cal

• 54 cal

• 300 cal

• 600 cal

Microcosmic salt is

• Na₄P₂O₇

• Na(NH₄)HPO₄

• Na(NH₃)HPO₄ 4H₂O

• MgNH₄PO₄