11.

A covalent molecule AB₃ has pyramidal structure. The number of lone pair and bond pair of electrons in the molecule are respectively

• 2 and 2

• 0 and 4

• 3 and 1

• 1 and 3

Excess of carbon dioxide is passed through 50 mL of 0.5 M calcium hydroxide solution. After the completion of the reaction, the solution was evaporated to dryness. The solid calcium carbonate was completely neutralised with 0.1 N hydrochloric acid. The volume of hydrochloric acid required is (Atomic mass of calcium = 40)

• 300 cm³

• 200 cm³

• 500 cm³

• 400 cm³

A bivalent metal has an equivalent mass of 32. The molecular mass of the metal nitrate is

• 182

• 168

• 192

• 188

The rms velocity of molecules of a gas of density 4 kg m^-3 and pressure 1.2 × 10⁵ Nm^-2 is

• 300 ms^-1

• 900 ms^-1

• 120 ms^-1

• 600 ms^-1

0.5 mole of each of H₂, SO₂ and CH₄ are kept in a container. A hole was made in the container. After 3 h, the order of partial pressures in the container will be

• pSO₂ > pH₂ > pCH₄

• pSO₂ > pCH₄ > pH₂

• pH₂ > pSO₂ > pCH₄ 

• pH₂ > pCH₄ >  pSO₂ 

The enthalpy of formation of NH₃ is - 46kJ mol^-1. The enthalpy change for the reaction is-

2NH₃ (g) → N₂ (g) + 3H₂ (g) 

• +184 kJ

• +23 kJ

• +92 kJ

• +46 kJ

5 moles of SO₂ and 5 moles of O₂ are allowed to react. At equilibrium, it was found that 60% of SO₂ is used up. If the partial pressure of the equilibrium mixture is one atmosphere, the partial pressure of O₂ is 

• 0.82 atm

• 0.52 atm

• 0.21 atm

• 0.41 atm

2HI (g) $\rightleftharpoons$ H₂ (g) + I₂ (g)

The equilibrium constant of the above reaction is 6.4 at 300 K. If 0.25 mole each of H₂ and I₂ are added to the system, the equilibrium constant will be

• 6.4

• 0.8

• 3.2

• 1.6

The order of stability of metal oxides is

• Al₂O₃ < MgO < Fe₂O₃ < Cr₂O₃

• Cr₂O₃ < MgO < Al₂O₃ < Fe₂O₃

• Fe₂O₃ < Cr₂O₃ < Al₂O₃ < MgO

• Fe₂O₃ < Al₂O₃ < Cr₂O₃ < MgO

The magnetic moment of a transition metal ion is $\sqrt{15}$ BM. Therefore, the number of unpaired electrons present in it is

• 3

• 4

• 1

• 2