A liquid can exist only

• between triple and critical points

• at any temperature above melting point

• between melting and critical points

• between boiling and melting points

HCl gas is covalent and NaCl is an ionic compound. This is because

• sodium is highly electropositrve

• hydrogen is a non-metal

• HCl is a gas

• electronegativity difference between H and Cl is less than 2.1

143.

Plot of Maxwell's distribution of velocities is given below.

Which of the following is correct about this plot?

• T₁ < T₂

• f₁ > f₂

• T₁> T₂

• V₁ < V₂

Formation of a solution from two components can be considered as

(1) pure solvent → separated solvent molecules, $∆$H₁

(2) pure solute → separated solute molecules, $∆$H₂

(3) separated solvent and solute molecules → solution, $∆$H₃ 

Solution so formed will be ideal if

• $∆{\mathrm{H}}_{\mathrm{soln}} = ∆{\mathrm{H}}_1 - ∆{\mathrm{H}}_2 - ∆$H₃

• $∆{\mathrm{H}}_{\mathrm{soln}} = ∆{\mathrm{H}}_3 - ∆{\mathrm{H}}_1 - ∆{\mathrm{H}}_2$

• $∆{\mathrm{H}}_{\mathrm{soln}} = ∆{\mathrm{H}}_1 + ∆{\mathrm{H}}_2 + ∆{\mathrm{H}}_3$

• $∆{\mathrm{H}}_{\mathrm{soln}} = ∆{\mathrm{H}}_1 + ∆{\mathrm{H}}_2 - ∆{\mathrm{H}}_3$

Calculate the total pressure in a 10.0 L cylinder which contains 0.4 g helium, 1.6 g oxygen and 1.4 g nitrogen at 27°C.

• 0.492 atm

• 49.2 atm

• 4.92 atm

• 0.0492 atm

The vapour pressure of two liquids P and Q are 80 and 60 torr, respectively. The total vapour pressure of solution obtained by mixing 3 moles of P and 2 moles of Q would be

• 140 torr

• 20 torr

• 68 torr

• 72 torr

For the following reaction in gaseous phase

CO (g) + $\frac{1}{2}$O₂ (g) → CO₂ (g) K_p/ K_c is

• (RT)^1/2

• (RT)^-1/2

• (RT)

• (RT)^-1

How many joules of heat are absorbed when 70.0 g of water is completely vaporised at its boiling point ?

• 23, 352

• 7,000

• 15,813

• 158, 130

Which of the following will increase with the increase in temperature ?

• Surface tension

• Viscosity

• Molality

• Vapour pressure

Lowering of vapour pressure is highest for

• 0.1 M BaCl₂

• 0.1 M glucose

• 0.1 M MgSO₄

• Urea