Practical & Analytical Chemistry · JEE Main previous year questions

2023 12 questions

1. Q622023 · 13 Apr 2023 · Shift 2

   In the wet tests for detection of various cations by precipitation, ${\mathrm{Ba}}^{2+}$ cations are detected by obtaining precipitate of

   1. A.${\mathrm{BaSO}}_4$
   2. B.${\mathrm{Ba}(\mathrm{OAc})}_2$
   3. C.${\mathrm{BaCO}}_3$
   4. D.$\mathrm{Ba}(\mathrm{ox})$ : Barium oxalate
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   Answer: C

2. Q652023 · 11 Apr 2023 · Shift 1

   Match List - I with List - II: | List - I Species | List - II Geometry/Shape | | :--- | :--- | | A. ${\mathrm{H}}_3{\mathrm{O}}^{+}$ | I. Tetrahedral | | B. Acetylide anion | II. Linear | | C. $\mathrm{N}{\mathrm{H}}_4^{+}$ | III. Pyramidal | | D. $\mathrm{Cl}{\mathrm{O}}_2^{-}$ | IV. Bent | Choose the correct answer from the options given below:

   1. A.A-III, B-I, C-II, D-IV
   2. B.A-III, B-II, C-I, D-IV
   3. C.A-III, B-IV, C-I, D-II
   4. D.A-III, B-IV, C-II, D-I
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   Answer: B

3. Q682023 · 11 Apr 2023 · Shift 1

   When a solution of mixture having two inorganic salts was treated with freshly prepared ferrous sulphate in acidic medium, a dark brown ring was formed whereas on treatment with neutral $\mathrm{FeC}{\mathrm{l}}_3$, it gave deep red colour which disappeared on boiling and a brown red ppt was formed. The mixture contains :

   1. A.$\mathrm{S}{\mathrm{O}}_3^{2-}\&{\mathrm{C}}_2{\mathrm{O}}_4^{2-}$
   2. B.$\mathrm{C}{\mathrm{H}}_3\mathrm{CO}{\mathrm{O}}^{-}\&\mathrm{N}{\mathrm{O}}_3^{-}$
   3. C.${\mathrm{C}}_2{\mathrm{O}}_4^{2-}\&\mathrm{N}{\mathrm{O}}_3^{-}$
   4. D.$\mathrm{S}{\mathrm{O}}_3^{2-}\&\mathrm{C}{\mathrm{H}}_3\mathrm{CO}{\mathrm{O}}^{-}$
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   Answer: B

4. Q692023 · 11 Apr 2023 · Shift 2
   
   1. A.
   2. B.
   3. C.
   4. D.
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   Answer: B

5. Q822023 · 8 Apr 2023 · Shift 1· Numerical answer

   The number of following factors which affect the percent covalent character of the ionic bond is _________ (A) Polarising power of cation (B) Extent of distortion of anion (C) Polarisability of the anion (D) Polarising power of anion

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   Answer: 3

6. Q622023 · 6 Apr 2023 · Shift 2

   Element not present in Nessler's reagent is :

   1. A.$\mathrm{I}$
   2. B.$\mathrm{N}$
   3. C.$\mathrm{K}$
   4. D.$\mathrm{Hg}$
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   Answer: B

7. Q712023 · 31 Jan 2023 · Shift 2

   Given below are two statements : Statement I: Upon heating a borax bead dipped in cupric sulphate in a luminous flame, the colour of the bead becomes green Statement II: The green colour observed is due to the formation of copper(I) metaborate In light of the above statements, choose the most appropriate answer from the options given below :

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

8. Q752023 · 29 Jan 2023 · Shift 1

   During the borax bead test with $\mathrm{CuS}{\mathrm{O}}_4$, a blue green colour of the bead was observed in oxidising flame due to the formation of :

   1. A.CuO
   2. B.$\mathrm{Cu}(\mathrm{B}{\mathrm{O}}_2{)}_2$
   3. C.$\mathrm{C}{\mathrm{u}}_3{\mathrm{B}}_2$
   4. D.Cu
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   Answer: B

9. Q772023 · 29 Jan 2023 · Shift 1

   "A" obtained by Ostwald's method involving air oxidation of $\mathrm{N}{\mathrm{H}}_3$, upon further air oxidation produces "B", "B" on hydration forms an oxoacid of Nitrogen along with evolution of "A". The oxoacid also produces "A" and gives positive brown ring test. Identify A and B, respectively :

   1. A.${\mathrm{N}}_2{\mathrm{O}}_3,\mathrm{N}{\mathrm{O}}_2$
   2. B.$\mathrm{N}{\mathrm{O}}_2,{\mathrm{N}}_2{\mathrm{O}}_5$
   3. C.$\mathrm{N}{\mathrm{O}}_2,{\mathrm{N}}_2{\mathrm{O}}_4$
   4. D.$\mathrm{NO},\mathrm{N}{\mathrm{O}}_2$
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   Answer: D

10. Q732023 · 25 Jan 2023 · Shift 1

    Match the List-I with List-II : $$\begin{array}{llll}& \text{List-I Cations}& & \text{List-II Group reagents}\\ \text{A.}& \mathrm{P}{\mathrm{b}}^{2+},\mathrm{C}{\mathrm{u}}^{2+}& \text{i)}& {\mathrm{H}}_2\mathrm{S}\text{ gas in presence of dilute HCl}\\ \text{B.}& \mathrm{A}{\mathrm{l}}^{3+},\mathrm{F}{\mathrm{e}}^{3+}& \text{ii)}& (\mathrm{N}{\mathrm{H}}_4{)}_2\mathrm{C}{\mathrm{O}}_3\text{ in presence of }\mathrm{N}{\mathrm{H}}_4\mathrm{OH}\\ \text{C.}& \mathrm{C}{\mathrm{o}}^{2+},\mathrm{N}{\mathrm{i}}^{2+}& \text{iii)}& \mathrm{N}{\mathrm{H}}_4\mathrm{OH}\text{ in presence of }\mathrm{N}{\mathrm{H}}_4\mathrm{Cl}\\ \text{D.}& \mathrm{B}{\mathrm{a}}^{2+},\mathrm{C}{\mathrm{a}}^{2+}& \text{iv)}& {\mathrm{H}}_2\mathrm{S}\text{ in presence of }\mathrm{N}{\mathrm{H}}_4\mathrm{OH}\end{array}$$ Correct match is -

    1. A.A $\to$ i, B $\to$ iii, C $\to$ iv, D $\to$ ii
    2. B.A $\to$ i, B $\to$ iii, C $\to$ ii, D $\to$ iv
    3. C.A $\to$ iii, B $\to$ i, C $\to$ iv, D $\to$ ii
    4. D.A $\to$ iv, B $\to$ ii, C $\to$ iii, D $\to$ i
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    Answer: A

11. Q702023 · 25 Jan 2023 · Shift 2

    A chloride salt solution acidified with dil.$\mathrm{HN}{\mathrm{O}}_3$ gives a curdy white precipitate, [A], on addition of $\mathrm{AgN}{\mathrm{O}}_3$. [A] on treatment with $\mathrm{N}{\mathrm{H}}_4\mathrm{OH}$ gives a clear solution B. A and B are respectively :

    1. A.$\mathrm{H}[\mathrm{AgC}{\mathrm{l}}_3]$ & $(\mathrm{N}{\mathrm{H}}_4)[\mathrm{Ag}(\mathrm{OH}{)}_2]$
    2. B.$\mathrm{AgCl}$ & $[\mathrm{Ag}(\mathrm{N}{\mathrm{H}}_3{)}_2]\mathrm{Cl}$
    3. C.$\mathrm{H}[\mathrm{AgC}{\mathrm{l}}_3]$ & $[\mathrm{Ag}(\mathrm{N}{\mathrm{H}}_3{)}_2]\mathrm{Cl}$
    4. D.$\mathrm{AgCl}$ & $(\mathrm{N}{\mathrm{H}}_4)[\mathrm{Ag}(\mathrm{OH}{)}_2]$
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    Answer: B

12. Q802023 · 25 Jan 2023 · Shift 2

    Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R Assertion A : The alkali metals and their salts impart characteristic colour to reducing flame. Reason R : Alkali metals can be detected using flame tests. In the light of the above statements, choose the most appropriate answer from the options given below :

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