A stream of electrons from a heated filament was passed between two charged plates kept at a potential difference V esu. If e and m are charge and mass of an electron, respectively, then the value of h/λ (where λ is wavelength associated with electron wave) is given by:

• 2meV

• 
• 
• 

The heats of combustion of carbon and carbon monoxide are −393.5 and −283.5 kJ mol−1, respectively. The heat of formation (in kJ) of carbon monoxide per mole is:

• 676.5

• -676.5

• -110.5

• -110.5

The species in which the N atom is in a state of sp hybridization is:

• NO₂^-

• NO₃^-

• NO₂
  

• NO₂
  

The equilibrium constant at 298 K for a reaction A+B ⇌ C+D is 100. If the initial concentration of all the four species were 1 M each, then equilibrium concentration of D (in mol L⁻¹ ) will be:

• 0.818

• 1.818

• 1.182

• 1.182

Which of the following atoms has the highest first ionisation energy?

• Na

• K

• Sc

• Sc

Two closed bulbs of equal volume (V) containing an ideal gas initially at pressure p_i and temperature T₁ are connected through a narrow tube of negligible volume as shown in the figure below. The temperature of one of the bulbs is then raised to T₂. The final pressure p_f is:

The hottest region of Bunsen flame shown in the figure below is:

• region 2

• region 3

• region 4

• region 4

8.

The distillation technique most suited for separating glycerol from spent-lye in the soap industry is:

• fractional distillation

• steam distillation

• distillation under reduced pressure

• distillation under reduced pressure

At 300 K and 1 atm, 15 mL of a gaseous hydrocarbon requires 375 mL air containing 20% O2 by volume for complete combustion. After combustion the gases occupy 330 mL. Assuming that the water formed is in liquid form and the volumes were measured at the same temperature and pressure, the formula of the hydrocarbon is:

• C₃H₈

• C₄H₈

• C₄H₁₂

• C₄H₁₂

Which one of the following statements about water is false?

• Water can act both as an acid and as a base.

• There is extensive intramolecular hydrogen bonding in the condensed phase.

• Ice formed by heavy water sinks in normal water.

• Ice formed by heavy water sinks in normal water.