Chemical & Ionic Equilibrium · JEE Main previous year questions

2021 25 questions

1. Q772021 · 1 Sept 2021 · Shift 2

   Match List - I with List - II : $$\begin{array}{llll}& \text{List - I}& & \text{List - II}\\ & \text{(Colloid Preparation Method)}& & \text{(Chemical Reaction)}\\ \text{(a)}& \text{Hydrolysis}& \text{(i)}& 2\mathrm{AuC}{\mathrm{l}}_3+3\mathrm{HCHO}+3{\mathrm{H}}_2\mathrm{O}\to 2\mathrm{Au}(\mathrm{sol})+3\mathrm{HCOOH}+6\mathrm{HCl}\\ \text{(b)}& \text{Reduction}& \text{(ii)}& \mathrm{A}{\mathrm{s}}_2{\mathrm{O}}_3+3{\mathrm{H}}_2\mathrm{S}\to \mathrm{A}{\mathrm{s}}_2{\mathrm{S}}_3(\mathrm{sol})+3{\mathrm{H}}_2\mathrm{O}\\ \text{(c)}& \text{Oxidation}& \text{(iii)}& \mathrm{S}{\mathrm{O}}_2+2{\mathrm{H}}_2\mathrm{S}\to 3\mathrm{S}(\mathrm{sol})+2{\mathrm{H}}_2\mathrm{O}\\ \text{(d)}& \text{Double Decomposition}& \text{(iv)}& \mathrm{FeC}{\mathrm{l}}_3+3{\mathrm{H}}_2\mathrm{O}\to \mathrm{Fe}(\mathrm{OH}{)}_3(\mathrm{sol})+3\mathrm{HCl}\end{array}$$ Choose the most appropriate answer from the options given below.

   1. A.(a)-(i), (b)-(iii), (c)-(ii), (d)-(iv)
   2. B.(a)-(iv), (b)-(i), (c)-(iii), (d)-(ii)
   3. C.(a)-(iv), (b)-(ii), (c)-(iii), (d)-(i)
   4. D.(a)-(i), (b)-(ii), (c)-(iv), (d)-(iii)
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   Answer: B

2. Q812021 · 1 Sept 2021 · Shift 2· Numerical answer

   The molar solubility of $\mathrm{Zn}(\mathrm{OH}{)}_2$ in $0.1\mathrm{M}\mathrm{NaOH}$ solution is $x\times 10^{-18}\mathrm{M}$. The value of x is ____. (Nearest integer) (Given : The solubility product of $\mathrm{Zn}(\mathrm{OH}{)}_2$ is $2\times 10^{-20}$)

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   Answer: 2

3. Q742021 · 26 Aug 2021 · Shift 2

   The number of non-ionisable hydrogen atoms present in the final product obtained from the hydrolysis of $\mathrm{PC}{\mathrm{l}}_5$ is :

   1. A.$0$
   2. B.$2$
   3. C.$1$
   4. D.$3$
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   Answer: A

4. Q822021 · 26 Aug 2021 · Shift 2· Numerical answer

   The equilibrium constant ${\mathrm{K}}_{\mathrm{c}}$ at 298 K for the reaction $\mathrm{A}+\mathrm{B}\rightleftharpoons \mathrm{C}+\mathrm{D}$ is 100. Starting with an equimolar solution with concentrations of A, B, C and D all equal to 1M, the equilibrium concentration of D is ___________ $\times 10^{-2}\text{ M}$. (Nearest integer)

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   Answer: 182

5. Q892021 · 26 Aug 2021 · Shift 2· Numerical answer

   The reaction rate for the reaction $[\mathrm{PtC}{\mathrm{l}}_4{]}^{2-}+{\mathrm{H}}_2\mathrm{O}\rightleftharpoons [\mathrm{Pt}({\mathrm{H}}_2\mathrm{O})\mathrm{C}{\mathrm{l}}_3{]}^{-}+{\mathrm{Cl}}^{-}$ was measured as a function of concentrations of different species. It was observed that $$\frac{-d\left[[\mathrm{PtC}{\mathrm{l}}_4{]}^{2-}\right]}{dt}=4.8\times 10^{-5}\left[[\mathrm{PtC}{\mathrm{l}}_4{]}^{2-}\right]-2.4\times 10^{-3}\left[[\mathrm{Pt}({\mathrm{H}}_2\mathrm{O})\mathrm{C}{\mathrm{l}}_3{]}^{-}\right][{\mathrm{Cl}}^{-}].$$ where square brackets are used to denote molar concentrations. The equilibrium constant ${\mathrm{K}}_{\mathrm{c}}=$ ___________. (Nearest integer)

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   Answer: 0

6. Q902021 · 26 Aug 2021 · Shift 2· Numerical answer

   A chloro compound "A". (i) forms aldehydes on ozonolysis followed by the hydrolysis. (ii) when vaporized completely 1.53 g of A, gives 448 mL of vapour at STP. The number of carbon atoms in a molecule of compound A is ___________.

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   Answer: 3

7. Q812021 · 27 Jul 2021 · Shift 2· Numerical answer

   The equilibrium constant for the reaction $\mathrm{A}(\mathrm{s})\rightleftharpoons \mathrm{M}(\mathrm{s})+\frac{1}{2}{\mathrm{O}}_2(\mathrm{g})$ is ${\mathrm{K}}_{\mathrm{p}}=4$. At equilibrium, the partial pressure of ${\mathrm{O}}_2$ is __________ atm. (Round off to the nearest integer)

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   Answer: 16

8. Q842021 · 27 Jul 2021 · Shift 2· Numerical answer

   10.0 mL of 0.05 M $\mathrm{KMn}{\mathrm{O}}_4$ solution was consumed in a titration with 10.0 mL of given oxalic acid dihydrate solution. The strength of given oxalic acid solution is __________ $\times 10^{-2}\text{ g/L}$. (Round off to the nearest integer)

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   Answer: 1575

9. Q852021 · 25 Jul 2021 · Shift 1· Numerical answer

   For the reaction $\mathrm{A}+\mathrm{B}\rightleftharpoons 2C$ the value of equilibrium constant is 100 at 298 K. If the initial concentration of all the three species is 1 M each, then the equilibrium concentration of C is $x\times 10^{-1}$ M. The value of x is ____. (Nearest integer)

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   Answer: 25

10. Q662021 · 25 Jul 2021 · Shift 2

    A reaction of benzonitrile with one equivalent $\mathrm{C}{\mathrm{H}}_3\mathrm{MgBr}$ followed by hydrolysis produces a yellow liquid "P". The compound "P" will give positive ____.

    1. A.Iodoform test
    2. B.Schiff's test
    3. C.Ninhydrin's test
    4. D.Tollen's test
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    Answer: A

11. Q902021 · 25 Jul 2021 · Shift 2· Numerical answer

    An LPG cylinder contains gas at a pressure of 300 kPa at $27^{\circ }$. The cylinder can withstand the pressure of $1.2\times 10^6$ Pa. The room in which the cylinder is kept catches fire. The minimum temperature at which the bursting of cylinder will take place is ____ ${}^{\circ }$ C. (Nearest integer)

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    Answer: 927

12. Q632021 · 22 Jul 2021 · Shift 2
    
    1. A.
    2. B.
    3. C.
    4. D.
    Show answer

    Answer: A, C, D

13. Q852021 · 22 Jul 2021 · Shift 2· Numerical answer

    Value of $K_P$ for the equilibrium reaction ${\mathrm{N}}_2{\mathrm{O}}_{4(\mathrm{g})}\rightleftharpoons 2N{\mathrm{O}}_{2(\mathrm{g})}$ at 288 K is 47.9. The $K_C$ for this reaction at same temperature is ____. (Nearest integer) (R = 0.083 L bar ${\mathrm{K}}^{-1}\mathrm{mo}{\mathrm{l}}^{-1}$)

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    Answer: 2

14. Q852021 · 20 Jul 2021 · Shift 1· Numerical answer

    $2{\text{SO}}_2(\text{g})+{\text{O}}_2(\text{g})\rightleftharpoons 2{\text{SO}}_3(\text{g})$ In an equilibrium mixture, the partial pressures are ${\text{P}}_{{\text{SO}}_3}=43\text{ kPa}$; ${\text{P}}_{{\text{O}}_2}=530\text{ Pa}$ and ${\text{P}}_{{\text{SO}}_2}=45\text{ kPa}$. The equilibrium constant ${\text{K}}_p=$ ________ $\times 10^{-2}$. (Nearest integer)

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    Answer: 172

15. Q632021 · 18 Mar 2021 · Shift 1
    
    1. A.
    2. B.
    3. C.
    4. D.
    Show answer

    Answer: C

16. Q742021 · 18 Mar 2021 · Shift 1

    Given below are two statements : One is labelled as Assertion A and the other labelled as reason R Assertion A : During the boiling of water having temporary hardness, $\mathrm{Mg}(\mathrm{HC}{\mathrm{O}}_3{)}_2$ is converted to $\mathrm{MgC}{\mathrm{O}}_3$. Reason R : The solubility product of $\mathrm{Mg}(\mathrm{OH}{)}_2$ is greater than that of $\mathrm{MgC}{\mathrm{O}}_3$. In the light of the above statements, choose the most appropriate answer from the options given below :

    1. A.Both A and R are true but R is not the correct explanation of A
    2. B.A is true but R is false
    3. C.Both A and R are true and R is the correct explanation of A
    4. D.A is false but R is true
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    Answer: D

17. Q822021 · 18 Mar 2021 · Shift 1· Numerical answer

    In order to prepare a buffer solution of pH 5.74, sodium acetate is added to acetic acid. If the concentration of acetic acid in the buffer is 1.0 M, the concentration of sodium acetate in the buffer is ___________ M. (Round off to the Nearest Integer). [Given : pKa (acetic acid) = 4.74]

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    Answer: 10

18. Q642021 · 18 Mar 2021 · Shift 2

    Given below are two statements : Statement I : ${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}$ and $\mathrm{AgCN}$ both can generate nucleophile. Statement II : $\mathrm{KCN}$ and $\mathrm{AgCN}$ both will generate nitrile nucleophile with all reaction conditions. Choose the most appropriate option :

    1. A.Statement I is false but statement II is true.
    2. B.Both statement I and statement II are true.
    3. C.Both statement I and statement II are false.
    4. D.Statement I is true but statement II is false.
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    Answer: D

19. Q862021 · 18 Mar 2021 · Shift 2· Numerical answer

    The gas phase reaction $2\mathrm{A}(g)\rightleftharpoons {\mathrm{A}}_2(g)$ at $400\mathrm{K}$ has $\Delta {\mathrm{G}}^{\circ }=+25.2\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1}$. The equilibrium constant ${\mathrm{K}}_{\mathrm{C}}$ for this reaction is ____ $\times 10^{-2}$. (Round off to the Nearest Integer). [Use : $\mathrm{R}=8.3\mathrm{J}\mathrm{mo}{\mathrm{l}}^{-1}{\mathrm{K}}^{-1}$, $\ln 10=2.3$, ${\log }_{10}2=0.30$, $1\mathrm{atm}=1\mathrm{bar}$] $[\mathrm{antilog}(-0.3)=0.501]$

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    Answer: 2

20. Q822021 · 16 Mar 2021 · Shift 1· Numerical answer

    Two salts ${\mathrm{A}}_2\mathrm{X}$ and $\mathrm{MX}$ have the same value of solubility product of $4.0\times 10^{-12}$. The ratio of their molar solubilities i.e. $\frac{S({\mathrm{A}}_2\mathrm{X})}{S(\mathrm{MX})}=$ _______. (Round off to the Nearest Integer)

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    Answer: 50

21. Q842021 · 16 Mar 2021 · Shift 1· Numerical answer

    For the reaction $A(g)\rightleftharpoons B(g)$ at $495\text{ K}$, ${\Delta }_{\mathrm{r}}{G}^{\circ }=-9.478{\text{ kJ mol}}^{-1}$. If we start the reaction in a closed container at $495\text{ K}$ with 22 millimoles of A, the amount of B in the equilibrium mixture is _______ millimoles. (Round off to the Nearest Integer). $[R=8.314{\text{ J mol}}^{-1}{\text{ K}}^{-1}$; $\ln 10=2.303]$

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    Answer: 20

22. Q872021 · 26 Feb 2021 · Shift 1· Numerical answer

    A homogeneous ideal gaseous reaction $A{B}_{2(g)}\rightleftharpoons A_{(g)}+2B_{(g)}$ is carried out in a 25 litre flask at $27^{\circ }\mathrm{C}$. The initial amount of $\mathrm{A}{\mathrm{B}}_2$ was 1 mole and the equilibrium pressure was 1.9 atm. The value of ${\mathrm{K}}_{\mathrm{p}}$ is $x\times 10^{-2}$. The value of x is _________. (Integer answer) $[R=0.08206\mathrm{d}{\mathrm{m}}^3\mathrm{atm}{\mathrm{K}}^{-1}\mathrm{mo}{\mathrm{l}}^{-1}]$

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    Answer: 72 to 75

23. Q862021 · 26 Feb 2021 · Shift 2· Numerical answer

    The pH of ammonium phosphate solution, if $\mathrm{p}{\mathrm{k}}_{\mathrm{a}}$ of phosphoric acid and $\mathrm{p}{\mathrm{k}}_{\mathrm{b}}$ of ammonium hydroxide are 5.23 and 4.75 respectively, is _________. (Nearest integer)

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    Answer: 7

24. Q632021 · 25 Feb 2021 · Shift 2

    The solubility of $\mathrm{Ca}(\mathrm{OH}{)}_2$ in water is : $[\text{Given : The solubility product of }\mathrm{Ca}(\mathrm{OH}{)}_2\text{ in water}=5.5\times 10^{-6}]$

    1. A.$1.11\times 10^{-6}$
    2. B.$1.11\times 10^{-2}$
    3. C.$1.77\times 10^{-6}$
    4. D.$1.77\times 10^{-2}$
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    Answer: B

25. Q762021 · 25 Feb 2021 · Shift 2

    Given below are two statements : Statement I : The pH of rain water is normally 5.6. Statement II : If the pH of rain water drops below 5.6, it is called acid rain. In the light of the above statements, choose the correct answer from the options given below :

    1. A.Both Statement I and Statement II are true.
    2. B.Both Statement I and Statement II are false.
    3. C.Statement I is true but Statement II is false.
    4. D.Statement I is false but Statement II is true.
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    Answer: A