Chemical & Ionic Equilibrium · JEE Main previous year questions

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2023 40 questions

Q662023 · 8 Apr 2023 · Shift 2
Given below are two statements: Statement I : In redox titration, the indicators used are sensitive to change in $pH$ of the solution. Statement II : In acid-base titration, the indicators used are sensitive to change in oxidation potential. In the light of the above statements, choose the most appropriate answer from the options given below
1. A.Both Statement I and Statement II are incorrect
2. B.Statement I is correct but Statement II is incorrect
3. C.Statement I is incorrect but Statement II is correct
4. D.Both Statement I and Statement II are correct
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Answer: A
Q832023 · 8 Apr 2023 · Shift 2· Numerical answer
The solubility product of $BaS O_{4}$ is $1 \times 1 0^{- 10}$ at $298 K$ . The solubility of $BaS O_{4}$ in $0.1 M K_{2} S O_{4} (aq)$ solution is ____ $\times 1 0^{- 9} g L^{- 1}$ (nearest integer). Given: Molar mass of $BaS O_{4}$ is $233 g mo l^{- 1}$
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Answer: 233
Q852023 · 8 Apr 2023 · Shift 2· Numerical answer
For complete combustion of ethene. $C_{2} H_{4} (g) + 3 O_{2} (g) \to 2C O_{2} (g) + 2 H_{2} O (l)$ the amount of heat produced as measured in bomb calorimeter is $1406 kJ mo l^{- 1}$ at $300 K$ . The minimum value of $TΔS$ needed to reach equilibrium is $(-)$ ____ $kJ$ . (Nearest integer) Given : $R = 8.3 J K^{- 1} mo l^{- 1}$
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Answer: 1411
Q662023 · 6 Apr 2023 · Shift 1
For a concentrated solution of a weak electrolyte ( $K_{e q} = equilibrium constant$ ) $A_{2} B_{3}$ of concentration ' $c$ ', the degree of dissociation ' $α$ ' is :
1. A. $(\frac{K _{e q}}{25 c ^{2}})^{\frac{1}{5}}$
2. B. $(\frac{K _{e q}}{108 c ^{4}})^{\frac{1}{5}}$
3. C. $(\frac{K _{e q}}{5 c ^{4}})^{\frac{1}{5}}$
4. D. $(\frac{K _{e q}}{6 c ^{5}})^{\frac{1}{5}}$
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Answer: B
Q612023 · 6 Apr 2023 · Shift 2
Formation of which complex, among the following, is not a confirmatory test of $P b^{2 +}$ ions :
1. A.lead chromate
2. B.lead iodide
3. C.lead sulphate
4. D.lead nitrate
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Answer: D
Q852023 · 6 Apr 2023 · Shift 2· Numerical answer
The equilibrium composition for the reaction $PC l_{3} + C l_{2} ⇌ PC l_{5}$ at $298 K$ is given below: $[PC l_{3}]_{eq} = 0.2 mol L^{- 1}$ , $[C l_{2}]_{eq} = 0.1 mol L^{- 1}$ , $[PC l_{5}]_{eq} = 0.40 mol L^{- 1}$ If $0.2 mol$ of $C l_{2}$ is added at the same temperature, the equilibrium concentration of $PC l_{5}$ is ___________ $\times 1 0^{- 2} mol L^{- 1}$ Given : $K_{c}$ for the reaction at $298 K$ is $20$
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Answer: 49
Q882023 · 6 Apr 2023 · Shift 2· Numerical answer
Consider the following pairs of solution which will be isotonic at the same temperature. The number of pairs of solutions is / are ___________. A. $1 M aq. NaCl$ and $2 M aq. urea$ B. $1 M aq. CaCl_{2}$ and $1.5 M aq. KCl$ C. $1.5 M aq. AlCl_{3}$ and $2 M aq. Na_{2} SO_{4}$ D. $2.5 M aq. KCl$ and $1 M aq. Al_{2} (SO_{4})_{3}$
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Answer: 4
Q622023 · 1 Feb 2023 · Shift 1
Which of the following are the example of double salt? A. $FeSO_{4} \cdot (NH_{4})_{2} SO_{4} \cdot 6 H_{2} O$ B. $CuSO_{4} \cdot 4 NH_{3} \cdot H_{2} O$ C. $K_{2} SO_{4} \cdot Al_{2} (SO_{4})_{3} \cdot 24 H_{2} O$ D. $Fe (CN)_{2} \cdot 4 KCN$ Choose the correct answer :
1. A.A, B and D only
2. B.B and D only
3. C.A and B only
4. D.A and C only
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Answer: D
Q892023 · 1 Feb 2023 · Shift 1· Numerical answer
(i) $X (g) ⇌ Y (g) + Z (g) K_{p 1} = 3$ (ii) $A (g) ⇌ 2 B (g) K_{p 2} = 1$ If the degree of dissociation and initial concentration of both the reactants $X (g)$ and $A (g)$ are equal, then the ratio of the total pressure at equilibrium $(\frac{p _{1}}{p _{2}})$ is equal to $x : 1$ . The value of $x$ is ________ (Nearest integer)
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Answer: 12
Q822023 · 31 Jan 2023 · Shift 1· Numerical answer
The logarithm of equilibrium constant for the reaction $Pd^{2 +} + 4 Cl^{-} ⇌ PdCl_{4}^{2 -}$ is __________ (Nearest integer) Given : $\frac{2.303 R T}{F} = 0.06 V$ $Pd_{(aq)}^{2 +} + 2 e^{-} ⇌ Pd (s) E^{⊖} = 0.83 V$ $PdCl_{4}^{2 -} (aq) + 2 e^{-} ⇌ Pd (s) + 4 Cl^{-} (aq) E^{⊖} = 0.65 V$
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Answer: 6
Q732023 · 31 Jan 2023 · Shift 2
The incorrect statement for the use of indicators in acid-base titration is :
1. A.Phenolphthalein is a suitable indicator for a weak acid vs strong base titration.
2. B.Methyl orange may be used for a weak acid vs weak base titration.
3. C.Methyl orange is a suitable indicator for a strong acid vs weak base titration.
4. D.Phenolphthalein may be used for a strong acid vs strong base titration.
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Answer: B
Q742023 · 31 Jan 2023 · Shift 2
The normal rain water is slightly acidic and its $pH$ value is 5.6 because of which one of the following?
1. A. $N_{2} O_{5} + H_{2} O \to 2 HNO_{3}$
2. B. $2 SO_{2} + O_{2} + 2 H_{2} O \to 2 H_{2} SO_{4}$
3. C. $4 NO_{2} + O_{2} + 2 H_{2} O \to 4 HNO_{3}$
4. D. $CO_{2} + H_{2} O \to H_{2} CO_{3}$
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Answer: D
Q792023 · 31 Jan 2023 · Shift 2
The Lewis acid character of boron tri halides follows the order :
1. A. $BI_{3} > BBr_{3} > BCl_{3} > BF_{3}$
2. B. $BCl_{3} > BF_{3} > BBr_{3} > BI_{3}$
3. C. $BF_{3} > BCl_{3} > BBr_{3} > BI_{3}$
4. D. $BBr_{3} > BI_{3} > BCl_{3} > BF_{3}$
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Answer: A
Q852023 · 31 Jan 2023 · Shift 2· Numerical answer
At $298 K$ , the solubility of silver chloride in water is $1.434 \times 1 0^{- 3} g L^{- 1}$ . The value of $- lo g K_{sp}$ for silver chloride is ___________. (Given mass of Ag is $107.9 g mol^{- 1}$ and mass of Cl is $35.5 g mol^{- 1}$ )
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Answer: 10
Q832023 · 30 Jan 2023 · Shift 1· Numerical answer
$600 mL$ of $0.01 M$ $HCl$ is mixed with $400 mL$ of $0.01 M$ $H_{2} SO_{4}$ . The pH of the mixture is ___________ $\times 1 0^{- 2}$ . (Nearest integer) $[Given lo g 2 = 0.30$ $lo g 3 = 0.48$ $lo g 5 = 0.69$ $lo g 7 = 0.84$ $lo g 11 = 1.04]$
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Answer: 186
Q822023 · 29 Jan 2023 · Shift 1· Numerical answer
Millimoles of calcium hydroxide required to produce 100 mL of the aqueous solution of pH 12 is $x \times 1 0^{- 1}$ . The value of $x$ is ____ (Nearest integer). Assume complete dissociation.
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Answer: 5
Q872023 · 29 Jan 2023 · Shift 1· Numerical answer
Water decomposes at 2300 K $H_{2} O (g) \to H_{2} (g) + \frac{1}{2} O_{2} (g)$ The percent of water decomposing at 2300 K and 1 bar is ____ (Nearest integer). Equilibrium constant for the reaction is $2 \times 1 0^{- 3}$ at 2300 K.
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Answer: 2
Q882023 · 29 Jan 2023 · Shift 1· Numerical answer
Consider the following reaction approaching equilibrium at $2 7^{\circ} C$ and 1 atm pressure $A + B k_{r} = 1 0^{2} ⇌ k_{f} = 1 0^{3} C + D$ The standard Gibb's energy change $(Δ_{r} G^{θ})$ at $2 7^{\circ} C$ is $(-)$ ____ $kJ mo l^{- 1}$ (Nearest integer). (Given : $R = 8.3 J K^{- 1} mo l^{- 1}$ and $ln 10 = 2.3$ )
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Answer: 6
Q732023 · 29 Jan 2023 · Shift 2
An indicator 'X' is used for studying the effect of variation in concentration of iodide on the rate of reaction of iodide ion with $H_{2} O_{2}$ at room temp. The indicator 'X' forms blue coloured complex with compound 'A' present in the solution. The indicator 'X' and compound 'A' respectively are :
1. A.Methyl orange and $H_{2} O_{2}$
2. B.Methyl orange and iodine
3. C.Starch and $H_{2} O_{2}$
4. D.Starch and iodine
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Answer: D
Q832023 · 29 Jan 2023 · Shift 2· Numerical answer
At $298 K$ $N_{2} (g) + 3 H_{2} (g) ⇌ 2N H_{3} (g), K_{1} = 4 \times 1 0^{5}$ $N_{2} (g) + O_{2} (g) ⇌ 2NO (g), K_{2} = 1.6 \times 1 0^{12}$ $H_{2} (g) + \frac{1}{2} O_{2} (g) ⇌ H_{2} O (g), K_{3} = 1.0 \times 1 0^{- 13}$ Based on above equilibria, then equilibrium constant of the reaction, $2N H_{3} (g) + \frac{5}{2} O_{2} (g) ⇌ 2NO (g) + 3 H_{2} O (g)$ is ____ $\times 1 0^{- 33}$ (Nearest integer).
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Answer: 4
Q742023 · 25 Jan 2023 · Shift 1
Reaction of thionyl chloride with white phosphorus forms a compound [A], which on hydrolysis gives [B], a dibasic acid. [A] and [B] are respectively :
1. A. $P_{4} O_{6}$ and $H_{3} P O_{3}$
2. B. $POC l_{3}$ and $H_{3} P O_{4}$
3. C. $PC l_{5}$ and $H_{3} P O_{4}$
4. D. $PC l_{3}$ and $H_{3} P O_{3}$
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Answer: D
Q822023 · 25 Jan 2023 · Shift 1· Numerical answer
A litre of buffer solution contains 0.1 mole of each of $N H_{3}$ and $N H_{4} Cl$ . On the addition of 0.02 mole of HCl by dissolving gaseous HCl, the pH of the solution is found to be ____ $\times 1 0^{- 3}$ (Nearest integer) [Given : $p K_{b} (N H_{3}) = 4.745$ $lo g 2 = 0.301$ $lo g 3 = 0.477$ $T = 298 K$ ]
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Answer: 9079
Q622023 · 25 Jan 2023 · Shift 2
When the hydrogen ion concentration $[H^{+}]$ changes by a factor of 1000, the value of pH of the solution ____
1. A.decreases by 2 units
2. B.increases by 2 units
3. C.decreases by 3 units
4. D.increases by 1000 units
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Answer: C
Q642023 · 24 Jan 2023 · Shift 1
Assertion A : Hydrolysis of an alkyl chloride is a slow reaction but in the presence of $NaI$ , the rate of the hydrolysis increases. Reason R : $I^{-}$ is a good nucleophile as well as a good leaving group. In the light of the above statements, choose the correct answer from the options given below
1. A.A is true but R is false
2. B.A is false but R is true
3. C.Both A and R are true and R is the correct explanation of A
4. D.Both A and R are true but R is NOT the correct explanation of A
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Answer: C
Q692023 · 24 Jan 2023 · Shift 1
1. A.
2. B.
3. C.
4. D.
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Answer: A