Which of the following electronic configurations has maximum energy?

The density of a gas A is thrice that of a gas B at the same temperature. The molecular weight of gas B is twice that of A. What will be the ratio of the pressures acting on B and A?

• $\frac{1}{4}$

• $\frac{7}{8}$

• $\frac{2}{5}$

• $\frac{1}{6}$

3.

For the reaction, H₂ + I₂ $\rightleftharpoons$ 2HI, K = 47.6. If the initial number of moles of each reactant and product is 1 mole then at equilibrium

• [I₂] = [H₂] , [I₂] > [HI]

• [I₂] = [H₂] , [I₂] < [HI]

• [I₂] < [H₂] , [I₂] = [HI]

• [I₂] > [H₂] , [I₂] = [HI]

The AsF₅ molecule is trigonal bipyramidal. The hybrid orbitals used by the As atoms for bonding are

• d_x²-y², d_z², s, p_x, p_y

• d_xy, s, p_x, p_y, p_z

• d_x²-y², s, p_x, p_y

• s, p_x, p_y, p_z, d_z²

Hydride of boron occurs as B₂H₆ but B₂Cl₆ does not exist. This is because

• p$\mathrm{\pi }$ - d$\mathrm{\pi }$ back bonding is possible in B₂H₆ but not in B₂Cl₆

• boron and hydrogen have almost equal values of electronegativity

• boron and chlorine have almost equal atomic sizes

• small hydrogen atoms can easily fit in between boron atoms but large chlorine atoms do not.

Calculate the overall complex dissociation equilibrium constant for the [Cu(NH₃)₄]²⁺ ions, given that stability  constant (${\mathrm{\beta }}_4$) for this complex is 2.1 $\times$ 10¹³.

• 8.27 $\times$ 10^-13

• 4.76 $\times$ 10^-14

• 2.39 $\times$ 10^-7

• 1.83 $\times$ 10¹⁴

The temperature dependence of a reaction is represented by the Arrhenius equation: 

ln k = -$\frac{{\mathrm{E}}_{\mathrm{a}}}{\mathrm{RT}}+\ln \mathrm{A}$

Which among the following is wrong conclusion about the given plot?

• Intercept of the line= ln A

• Slope = -$\frac{{\mathrm{E}}_{\mathrm{a}}}{\mathrm{RT}}$

• Reaction with high activation energy is more temperature sensitive than that of low activation energy (E_a).

• Slope = - $\frac{{\mathrm{E}}_{\mathrm{a}}}{\mathrm{R}}$

Which of the following oxoacids of phosphorus is a reducing agent and a monobasic acid as well?

• H₄P₂O₅

• HPO₃

• H₃PO₃

• H₃PO₂

Ionisation potential of hydrogen atom is 13.6 eV. Hydrogen atom in ground state is excited by monochromatic light of energy 12.1 eV. The spectral lines emitted by hydrogen according to Bohr's theory will be

• one

• two

• three

• four

K_a for HCN is 5 x 10^-10 at 25°C. For maintaining a constant pH = 9, the volume of 5 M KCN solution required to be added to 10 mL of 2 M HCN solution is

• 4 mL

• 2.5 mL

• 2 mL

• 6.4 mL