Practical & Analytical Chemistry · JEE Main previous year questions

2024 10 questions

1. Q762024 · 9 Apr 2024 · Shift 2

   Match List I with List II $$\begin{array}{llll}& \text{LIST I}& & \text{LIST II}\\ & \text{(Test)}& & \text{(Observation)}\\ \text{A.}& \mathrm{B}{\mathrm{r}}_2\text{ water test}& \text{I.}& \text{Yellow orange or orange red precipitate formed}\\ \text{B.}& \text{Ceric ammonium nitrate test}& \text{II.}& \text{Reddish orange colour disappears}\\ \text{C.}& \text{Ferric chloride test}& \text{III.}& \text{Red colour appears}\\ \text{D.}& \text{2, 4 - DNP test}& \text{IV.}& \text{Blue, Green, Violet or Red colour appears}\end{array}$$ Choose the correct answer from the options given below:

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

2. Q882024 · 9 Apr 2024 · Shift 2· Numerical answer

   Consider the following test for a group-IV cation. ${\mathrm{M}}^{2+}+{\mathrm{H}}_2\mathrm{S}\to \mathrm{A}$ (Black precipitate)$+\mathrm{byproduct}$ $\mathrm{A}+\mathrm{aqua}\mathrm{regia}\to \mathrm{B}+\mathrm{NOCl}+\mathrm{S}+{\mathrm{H}}_2\mathrm{O}$ $\mathrm{B}+\mathrm{KN}{\mathrm{O}}_2+\mathrm{C}{\mathrm{H}}_3\mathrm{COOH}\to \mathrm{C}+\mathrm{byproduct}$ The spin-only magnetic moment value of the metal complex C is ____ BM (Nearest integer)

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   Answer: 0

3. Q702024 · 8 Apr 2024 · Shift 1

   Match List I with List II LIST I (Name of the test) A. Borax bead test B. Charcoal cavity test C. Cobalt nitrate test D. Flame test LIST II (Reaction sequence involved) [M is metal] I. $\mathrm{MC}{\mathrm{O}}_3\to \mathrm{MO}\underset{+\mathrm{\Delta }}{\overset{\mathrm{Co}(\mathrm{N}{\mathrm{O}}_3{)}_2}{\to }}\mathrm{CoO}\cdot \mathrm{MO}$ II. $\mathrm{MC}{\mathrm{O}}_3\to \mathrm{MC}{\mathrm{l}}_2\to {\mathrm{M}}^{2+}$ III. $\mathrm{MS}{\mathrm{O}}_4\underset{\mathrm{\Delta }}{\overset{\mathrm{N}{\mathrm{a}}_2{\mathrm{B}}_4{\mathrm{O}}_7}{\to }}\mathrm{M}(\mathrm{B}{\mathrm{O}}_2{)}_2\to \mathrm{MB}{\mathrm{O}}_2\to \mathrm{M}$ IV. $\mathrm{MS}{\mathrm{O}}_4\underset{\mathrm{\Delta }}{\overset{\mathrm{N}{\mathrm{a}}_2\mathrm{C}{\mathrm{O}}_3}{\to }}\mathrm{MC}{\mathrm{O}}_3\to \mathrm{MO}\to \mathrm{M}$ Choose the correct answer from the options given below:

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

4. Q802024 · 8 Apr 2024 · Shift 2

   In qualitative test for identification of presence of phosphorus, the compound is heated with an oxidising agent. Which is further treated with nitric acid and ammonium molybdate respectively. The yellow coloured precipitate obtained is :

   1. A.$\mathrm{N}{\mathrm{a}}_3\mathrm{P}{\mathrm{O}}_4\cdot 12Mo{\mathrm{O}}_3$
   2. B.$(\mathrm{N}{\mathrm{H}}_4{)}_3\mathrm{P}{\mathrm{O}}_4\cdot 12(\mathrm{N}{\mathrm{H}}_4{)}_2\mathrm{Mo}{\mathrm{O}}_4$
   3. C.$\mathrm{MoP}{\mathrm{O}}_4\cdot 21N{\mathrm{H}}_4\mathrm{N}{\mathrm{O}}_3$
   4. D.$(\mathrm{N}{\mathrm{H}}_4{)}_3\mathrm{P}{\mathrm{O}}_4\cdot 12Mo{\mathrm{O}}_3$
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   Answer: D

5. Q632024 · 30 Jan 2024 · Shift 1

   Given below are two statements : Statement (I) : The gas liberated on warming a salt with dil ${\mathrm{H}}_2\mathrm{S}{\mathrm{O}}_4$, turns a piece of paper dipped in lead acetate into black, it is a confirmatory test for sulphide ion. Statement (II) : In statement-I the colour of paper turns black because of formation of lead sulphite. 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 false
   2. B.Statement I is true but Statement II is false
   3. C.Both Statement I and Statement II are true
   4. D.Statement I is false but Statement II is true
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   Answer: B

6. Q732024 · 30 Jan 2024 · Shift 1

   Sugar which does not give reddish brown precipitate with Fehling's reagent, is :

   1. A.Glucose
   2. B.Sucrose
   3. C.Lactose
   4. D.Maltose
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   Answer: B

7. Q682024 · 29 Jan 2024 · Shift 1

   In chromyl chloride test for confirmation of $\mathrm{C}{\mathrm{l}}^{-}$ ion, a yellow solution is obtained. Acidification of the solution and addition of amyl alcohol and $10\%{\mathrm{H}}_2{\mathrm{O}}_2$ turns organic layer blue indicating formation of chromium pentoxide. The oxidation state of chromium in that is

   1. A.$+6$
   2. B.$+5$
   3. C.$+3$
   4. D.$+10$
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   Answer: A

8. Q612024 · 29 Jan 2024 · Shift 2

   On passing a gas, 'X', through Nessler's reagent, a brown precipitate is obtained. The gas 'X' is

   1. A.$\mathrm{C}{\mathrm{l}}_2$
   2. B.$\mathrm{C}{\mathrm{O}}_2$
   3. C.$\mathrm{N}{\mathrm{H}}_3$
   4. D.${\mathrm{H}}_2\mathrm{S}$
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   Answer: C

9. Q762024 · 29 Jan 2024 · Shift 2

   A reagent which gives brilliant red precipitate with Nickel ions in basic medium is

   1. A.dimethyl glyoxime
   2. B.sodium nitroprusside
   3. C.meta-dinitrobenzene
   4. D.neutral $\mathrm{FeC}{\mathrm{l}}_3$
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   Answer: A

10. Q892024 · 29 Jan 2024 · Shift 2· Numerical answer

    The oxidation number of iron in the compound formed during brown ring test for $\mathrm{N}{\mathrm{O}}_3^{-}$ ion is _________.

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    Answer: 1