JEE Advanced (Fill in the Blanks): Equilibrium

Fill in the Blanks

Q.1. The conjugate base of   in aqueous solution is ...........                  (1982 - 1 Mark)

Ans. 

Solution. ; Conjugate base = Acid - H⁺

∴ Conjugate base of 

Q.2. An element which can exist as a positive ion in acidic solution and also as a negative ion in basic solution is said to be ............... .                (1984 - 1 Mark)

Ans. amphoteric

Solution. amphoteric ; because amphoteric substances show properties of both acids and basic

Q.3. For a given reversible reaction at a fixed temperature, equilibrium constants K_p and K_c are related by........              (1994 - 1 Mark)

Ans. K_p = K_c (RT)^Δn

Solution. K_p = K_c (RT)^Δn ;

Here Δn = No. of moles of gaseous products  - no. of moles of gaseous reactants

R = gas constant, and T = absolute temperature.

Q.4. A ten - fold increase in pressure on the reaction , at equilibrium results in .... in K_P.                (1996 - 1 Mark)

Ans. no change

Solution. no change; (K_p of an equilibrium reaction is independent of the pressure of the system.)

Q.5. In the reaction I^-+I₂ → I₃^- , the Lewis acid is ........... .                 (1997 - 1 Mark)

Ans. I₂

Solution. I₂. ∵ electron acceptors are Lewis acids.

True/False

Q.1. Aluminium chloride (AlCl₃) is a Lewis acid because it can donate electrons.              (1982 - 1 Mark)

Ans. F

Solution. False : AlCl₃ is a Lewis acid (although they do not have a proton, aprotic) because it accepts electrons (octet being incomplete).

Q.2. If equilibrium constant for the reaction   is K, then for the backward reaction  the equilibrium constant is 1/K.       (1984 - 1 Mark)

Ans. F

Solution. False : 

Q.3. When a liquid and its vapour are at equilibrium and the pressure is suddenly decreased, cooling occurs.                 (1984 - 1 Mark)

Ans. T

Solution. True : Lower the pressure, lower will be boiling point. More liquid will vapourise and temperature decreases.

Q.4. Solubility of sodium hydroxide increases with increase in temperature.               (1985 - ½ Mark)

Ans. F

Solution. TIPS/Formulae : Dissolution of NaOH is exothermic.

False : When a solute like NaOH is added to a solvent exothermic dissolution takes place. An increase in temperature always favour endothermic process. So solutes having exothermic dissolution shows a decrease in their solubility with temperature