Hydrocarbons · JEE Main previous year questions

2021 6 questions

1. Q822021 · 22 Jul 2021 · Shift 2· Numerical answer

   Methylation of 10 g of benzene gave 9.2 g of toluene. Calculate the percentage yield of toluene __________. (Nearest integer)

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   Answer: 78

2. Q682021 · 18 Mar 2021 · Shift 1

   Match List - I with List - II : $$\begin{array}{llll}& \text{List - I (Chemicals)}& & \text{List - II (Use / Preparation / Constituent)}\\ \text{(a)}& \text{Alcoholic potassium hydroxide}& \text{(i)}& \text{Electrodes in batteries}\\ \text{(b)}& Pd/BaS{\mathrm{O}}_4& \text{(ii)}& \text{Obtained by addition reaction}\\ \text{(c)}& \text{BHC (Benzene hexachloride)}& \text{(iii)}& \text{Used for }\beta \text{ - elimination reaction}\\ \text{(d)}& \text{Polyacetylene}& \text{(iv)}& \text{Lindlar’s catalyst}\end{array}$$ Choose the most appropriate match :

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

3. Q732021 · 18 Mar 2021 · Shift 1

   Match List - I with List - II $$\begin{array}{llll}& \text{List - I}& & \text{List - II}\\ & \text{(process)}& & \text{(catalyst)}\\ \text{(a)}& \text{Deacon’s process}& \text{(i)}& \text{ZSM-5}\\ \text{(b)}& \text{Contact process}& \text{(ii)}& \mathrm{CuC}{\mathrm{l}}_2\\ \text{(c)}& \text{Cracking of hydrocarbons}& \text{(iii)}& \text{Particles ’Ni’}\\ \text{(d)}& \text{Hydrogenation of vegetable oils}& \text{(iv)}& {\mathrm{V}}_2{\mathrm{O}}_5\end{array}$$ Choose the most appropriate answer from the options given below :

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

4. Q612021 · 16 Mar 2021 · Shift 1
   
   1. A.
   2. B.
   3. C.
   4. D.
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   Answer: B

5. Q692021 · 26 Feb 2021 · Shift 2
   
   1. A.(a) $\to$ (ii), (b) $\to$ (iv), (c) $\to$ (i), (d) $\to$ (iii)
   2. B.(a) $\to$ (iii), (b) $\to$ (iv), (c) $\to$ (i), (d) $\to$ (ii)
   3. C.(a) $\to$ (iii), (b) $\to$ (i), (c) $\to$ (iv), (d) $\to$ (ii)
   4. D.(a) $\to$ (ii), (b) $\to$ (i), (c) $\to$ (iv), (d) $\to$ (iii)
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   Answer: A

6. Q612021 · 25 Feb 2021 · Shift 2

   The correct sequence of reagents used in the preparation of 4-bromo-2-nitroethyl benzene from benzene is :

   1. A.$C{H}_{3}COCl/AlC{l}_3$, $B{r}_2/AlB{r}_3$, $HN{O}_3/H_{2}S{O}_4$, $Zn/HCl$
   2. B.$C{H}_{3}COCl/AlC{l}_3$, $Zn-Hg/HCl$, $B{r}_2/AlB{r}_3$, $HN{O}_3/H_{2}S{O}_4$
   3. C.$B{r}_2/AlB{r}_3$, $C{H}_{3}COCl/AlC{l}_3$, $HN{O}_3/H_{2}S{O}_4$, $Zn/HCl$
   4. D.$HN{O}_3/H_{2}S{O}_4$, $B{r}_2/AlC{l}_3$, $C{H}_{3}COCl/AlC{l}_3$, $Zn-Hg/HCl$
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   Answer: B