Which one of the following compounds has the smallest bond angle in its molecule ?

• SO₂

• OH₂

• SH₂

• NH₃

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

If at 298 K the bond energies of C-H, C-C, C=C and H-H bonds are respectively 414, 347, 615 and 435 kJ mol^-1, the value of enthalpy change for the reaction

H₂C=CH₂ (g) + H₂ (g) → H₃C - CH₃ (g) at 298 K will be

• +250 kJ

• -250 kJ

• +125 kJ

• -125 kJ

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 solubilities of carbonates decrease down the magnesium group due to a decrease in

• lattice energies of solids

• hydration energies of cations

• inter-ionic attraction

• entropy of solution formation

Due to the presence of an unpaired electron free radicals are

• cations

• anions

• chemically inactive

• chemically reactive

Consider the reaction,

N₂ + 3H₂ → 2NH₃

carried out at constant temperature and pressure. If $∆$H and $∆$U are the enthalpy and internal energy changes for the reaction, which of the following expression is true?

• $∆\mathrm{H} > ∆\mathrm{U}$

• $∆\mathrm{H} <∆\mathrm{U}$

• $∆\mathrm{H} = ∆\mathrm{U}$

• $∆$H = 0

The molecular shapes of SF₄, CF₄ and XeF₄ are

• different with 1, 0 and 2 lone pairs of electrons on the central atom, respectively

• different with 0, 1 and 2 lone pairs of electrons on the central atom, respectively

• the same with 1, 1 and 1 lone pair of electrons on the central atoms, respectively

• the same with 2, 0 and 1 lone pairs of electrons on the central atom, respectively

The wavelength of the radiation emitted, when in a hydrogen atom electron falls from infinity to stationary state 1, would be (Rydberg constant = 1.097 × 10⁷ m^-1)

• 91 nm

• 192 nm

• 406 nm

• 9.1 × 10^-8 nm

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 = $\frac{1}{[{\mathrm{O}}_2{]}^5}$