Ionic Equilibrium PYQs Set 5 (PDF)

Set 5 of 10 · Questions 121-150 of 274

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Mere Teacher · Previous Year Questions JEE Main Chemistry · Ionic Equilibrium · Set 5 (Q121-150)
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121. $In liquid‐gas equilibrium, the pressure of vapours above the liquid is constant at$ (1) $constant temperature$ (2) $low temperature$ (3) $high temperature$ (4) $none of these.$ 122. $Observe the following equilibrium at T (K) H_{2} (g) + I_{2} (g) ⇌ 2 HI (g) Which one of the following does not disturb the above equilibrium?$ (1) $Addition of H_{2} (g)$ (2) $Removal of HI (g)$ (3) $Addition of I_{2} (g)$ (4) $Addition of He (g)$ 123. $Which of the following fluoro‐compounds is most likely to behave as a Lewis base?$ (1) $B F_{3}$ (2) $P F_{3}$ (3) $C F_{4}$ (4) $S i F_{4}$ 124. $If the molar concentrations of base and its conjugate acid are same, then pOH of the buffer solution is$ (1) $same as p K_{b} of base$ (2) $same as p K_{a} of base$ (3) $same as p K_{a} of acid$ (4) $same as p K_{b} of acid$ 125. $Zirconium phosphate [Z r_{3} (P O_{4})_{4}] dissociates into three zirconium cations of charge +4 and four phosphate anions of charge -3. If molar solubility of zirconium phosphate is denoted by S and its solubility product by K_{s p} then which of the following relationship between S and K_{s p} is correct?$ (1) $S = {K_{s p} / (6912)^{1/7}}$ (2) $S = {K_{s p} /144}^{1/7}$ (3) $S = (K_{s p} /6912)^{1/7}$ (4) $S = {K_{s p} /6912}^{7}$ 126. $Consider a weak base ' B ' of pK_{b} = 5.699 .^{’} x^{’} mL of 0.02 M HCl and ' y ' mL of 0.02 M weak base ' B ' are mixed to make 100 mL of a buffer of pH 9 at 25^{\circ} C . The values of ' x' and ' y' respectively are: [Given: log 2 = 0.3010, log 3 = 0.4771, log 5 = 0.699]$ (1) $x y 85.7 14.3$ (2) $x y 14.3 85.7$ (3) $x y 11.1 88.9$ (4) $x y 42.7 57.3$ 127. $Which of the following expression is correct$ (1) $Δ G = - RT ln K$ (2) $Δ G = \frac{1}{R T ^{2} ln K}$ (3) $Δ G^{0} = - RT ln K$ (4) $Δ G^{0} = - \frac{1}{R T ^{2} ln K}$ 128. $30.0 mL of the given HCl solution requires 20.0 mL of 0.1 M sodium carbonate solution for complete neutralisation. What is the volume of this HCl solution required to neutralise 30.0 mL of 0.2 MNaOH solution?$ (1) $25 mL$ (2) $50 mL$ (3) $90 mL$ (4) $45 mL$ 129. $Equimolar solutions of the following substances were prepared separately. Which one of these will record the highest p H value?$ (1) $B a C l_{2}$ (2) $A l C l_{3}$ (3) $L i C l$ (4) $B e C l_{2}$ 130. $At 780 K and 10 atmosphere pressure the equilibrium constant for the reaction 2 A (g) ⇌ B (g) + C (g) is 3.52 . At the same temperature and 7.04 atmosphere pressure, the equilibrium constant for the same reaction is$ (1) $7.04$ (2) $3.52$ (3) $10.56$ (4) $5.23$ 131. $Which of the following salts is the most basic in aqueous solution?$ (1) $F e C l_{3}$ (2) $Pb (C H_{3} C O O)_{2}$ (3) $Al (C N)_{3}$ (4) $C H_{3} COOK$ 132. $A gas is allowed to expand in an insulated container against a constant external pressure of 2.5 bar from 4.5 dm^{3} to 7 \times 10^{- 3} m^{3} . What is the change in internal energy of the gas?$ (1) $- 3.25 J$ (2) $- 312.5 J$ (3) $112.3 J$ (4) $- 625 J$ 133. $The pH of a & 0.02 & & M & & NH_{4} C solution will be [given K_{b} (NH_{4} OH) = 10^{- 5} and log 2 = 0.301]$ (1) $2.65$ (2) $4.35$ (3) $4.65$ (4) $5.35$ 134. $For the equilibrium 2 H_{2} O ⇌ H_{3} O^{+} + OH^{-} the value of Δ G^{\circ} 298 K is approximately:$ (1) $100 kJ mol^{- 1}$ (2) $- 80 kJ mol^{- 1}$ (3) $80 kJ mol^{- 1}$ (4) $- 100 kJ mol^{- 1}$ 135. $Given below are two statements : Statement (I) : A Buffer solution is the mixture of a salt and an acid or a base mixed in any particular quantities. Statement (II) : Blood is naturally occurring buffer solution whose pH is maintained by H_{2} CO_{3} / HCO_{3}^{-} Θ concentrations. In the light of the above statements, choose the correct answer from the options given below :$ (1) $Statement I is true but Statement II is false$ (2) $Both Statement I and Statement II are true$ (3) $Statement I is false but Statement II is true$ (4) $Both Statement I and Statement II are false$ 136. $3 O_{2} (g) ⇌ 2 O_{3} (g) for the given reaction at 298 K, K_{c} is found to be 3.0 \times 10^{- 59} . If the concentration of O_{2} at equilibrium is 0.040 M then concentration of O_{3} in M is$ (1) $1.2 \times 10^{21}$ (2) $4.38 \times 10^{- 32}$ (3) $1.9 \times 10^{- 63}$ (4) $2.4 \times 10^{31}$ 137. $A weak acid HX at 25ºC has the dissociation constant 1 \times 1 0^{-5} . It forms a salt NaX on reaction with caustic soda. The percentage hydrolysis of 0.1 M solution of NaX is :$ (1) $0.0001%$ (2) $0.01 %$ (3) $0.1 %$ (4) $0.15 %$ 138. $In which of the following salts, only cationic hydrolysis is involved?$ (1) $CH_{3} COONH_{4}$ (2) $CH_{3} COONa$ (3) $NH_{4} Cl$ (4) $Na_{2} SO_{4}$ 139. $A mixture of 100 m mol of Ca (O H)_{2} and 2 g of sodium sulphate was dissolved in water and the volume was made up to 100 mL. The mass of calcium sulphate formed and the concentration of O H^{-} in resulting solution, respectively, are : (Molar mass of Ca (O H)_{2}, N a_{2} S O_{4} and C a S O_{4} are 74, 143 and 136 g m o l^{-1}, respectively; K_{s p} of Ca (O H)_{2} is 5.5 \times 1 0^{-6})$ (1) $13.6 g, 0.14 mol L^{-1}$ (2) $13.6 g, 0.28 mol L^{-1}$ (3) $1.9 g, 0.28 mol L^{-1}$ (4) $1.9 g, 0.14 mol L^{-1}$ 140. $The solubility of Mg (O H)_{2} is s moles/liter. The solubility product under the same condition is :$ (1) $4 s^{3}$ (2) $3 s^{4}$ (3) $4 s^{2}$ (4) $s^{3}$ 141. $One mole H_{2} O (g) and one mole CO (g) are taken in 1 L flask and heated to 725 K . At equilibrium, 40 % (by mass) of water reacted with CO (g) as follows. H_{2} O (g) + CO (g) ⇌ H_{2} (g) + CO_{2} (g) Its K_{p} value is$ (1) $2.220$ (2) $0.444$ (3) $4.440$ (4) $0.222$ 142. $Which of the following salts will give highest p H in water?$ (1) $KCl$ (2) $N a C l$ (3) $N a_{2} C O_{3}$ (4) $C u S O_{4}$ 143. $Match the following columns: Column-I (Acid) A. HCN B. H_{2} C_{2} O_{4} c. H2S D. Niacin Column-II (K_{a}) (ionisation constant)] 1. 6.8 \times 10-4 2. 8.9 \times 10-4 3. 4.9 \times 10-10 4. 5.6 \times 10-2 5. 1.5 \times 10-5 The correct match is Codes: A B C D$ (1) $1345$ (2) $5234$ (3) $2345$ (4) $3425$ 144. $Find the value of the equilibrium constant (K) of a reaction at 300 K, when standard Gibbs free energy change is - 25 kJ mol^{- 1} ? (Consider R = 8.33 mol^{- 1} K^{- 1})$ (1) $e^{8}$ (2) $e^{9}$ (3) $e^{10}$ (4) $e^{11}$ 145. $Calculate the number of moles of NaOH required to completely neutralise 100 g of 118 % oleum$ (1) $2.4$ (2) $1.2$ (3) $4.8$ (4) $8.4$ 146. $The dissociation constant of a substituted benzoic acid at 25ºC is 1.0 \times 1 0^{-4} . The pH of 0.01 M solution of its sodium salt is :$ 147. $Consider the dissociation equilibrium of the following weak acid HA ⇌ H^{+} (aq) + A^{-} (aq) If the pKa of the acid is 4 , then the pH of 10 mMHA solution is____.(Nearest integer) [Given: The degree of dissociation can be neglected with respect to unity]$ 148. $0.01 moles of a weak acid HA (K_{a} = 2.0 \times 10^{- 6}) is dissolved in 1.0 L of 0.1 MHCl solution. The degree ofdissociation of HA is_____\times 10^{- 5} (Round of to the Nearest Integer). [Neglect volume change on adding HA. Assume degree of dissociation << 1]$ 149. $The molar solubility of Zn (O H)_{2} in 0.1 M NaOH solution is x \times 1 0^{- 18} M. The value of x is ____. (Nearest integer) (Given : The solubility product of Zn (O H)_{2} is 2 \times 1 0^{- 20})$ 150. $The solubility product of PbI_{2} is 8 \times 10^{- 9} . The solubility of lead iodide in 0.1 molar solution of lead nitrate is x \times 10^{- 6} mol/L. The value of x is ______(Rounded off to the nearest integer) [Given: 2 = 1.41]$