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JEE MAIN - Chemistry (2019 - 11th January Morning Slot)

1
For the chemical reaction X $$\rightleftharpoons$$ Y, the standard reaction Gibbs energy depends on temperature T (in K) as $$\Delta $$rGo (in kJ mol–1) = 120 $$ - {3 \over 8}$$ T.

The major component of the reaction mixture at T is :
Answer
(D)
X if T = 315 K
2
Consider the reaction
N2(g) + 3H2(g) $$\rightleftharpoons$$ 2NH3(g)

The equilibrium constant of the above reaction is Kp. If pure ammonia is left to dissociate, the partial pressure of ammonia at equilibrium is given by (Assume that PNH3 << Ptotal at equilibrium)
Answer
(C)
$${{{3^{{3 \over 2}}}{K_P^{{1 \over 2}}}{P^2}} \over 16}$$
3
A 10 mg effervescent tablet containing sodium bicarbonate and oxalic acid releases 0.25 ml of CO2 at T = 298.15 K and p = 1 bar. If molar volume of CO2 is 25.0 L under such condition, what is the percentage of sodium bicarbonate in each tablet ?
[Molar mass of NaHCO3 = 84 g mol–1]
Answer
(C)
8.4
4
The correct order of the atomic radii of C, Cs, Al, and S is :
Answer
(C)
C < S < Al < Cs
5
For the cell Zn(s) |Zn2+ (aq)| |Mx+ (aq)| M(s), different half cells and their standard electrode potentials are given below :

Mx+ (aq)/M(s) Au3+(aq)/Au(s) Ag+(aq)/Ag(s) Fe3+(aq)/Fe2+ (aq) Fe2+(aq)/Fe(s)
E0Mx+/M/(V) 1.40 0.80 0.77 $$-$$0.44


If $$E_{z{n^{2 + }}/zn}^0$$ = $$-$$ 0.76 V, which cathode will give maximum value of Eocell per electron transferred?
Answer
(A)
Ag+/Ag
6
The element that usually does NOT show variable oxidation states is :
Answer
(C)
Sc
7
Heat treatment of muscular pain involves radiation of wavelength of about 900 nm. Which spectral line of H atom is suitable for this purpose?

[RH = 1 $$ \times $$ 105 cm–1, h = 6.6 $$ \times $$ 10–34 Js, c = 3 $$ \times $$ 108 ms–1]
Answer
(C)
Paschen, $$\infty $$ $$ \to $$ 3
8
Match the metals (column I) with the coordination compound(s)/enzyme(s) (column II)

(Column I) Metals
 (Column II) Coordination
compounds(s) enzyme(s)
(A) Co (i) Wilkinson catalyst
(B) Zn (ii) Chlorophyl
(C) Rh (iii) Vitamin B12
(D) Mg (iv) Carbonic anhydrase
Answer
(A)
(A)-(iii); (B)-(iv); (C)-(i); (D)-(ii)
9
If a reaction follows the Arrhenius equation, the plot ln k vs $${1 \over {\left( {RT} \right)}}$$ gives straight line with a gradient ($$-$$ y) unit.

The energy required to active the reactant is :
Answer
(A)
y unit
10
The major product of the following reaction is :

JEE Main 2019 (Online) 11th January Morning Slot Chemistry - Alcohols, Phenols and Ethers Question 133 English
Answer
(B)
JEE Main 2019 (Online) 11th January Morning Slot Chemistry - Alcohols, Phenols and Ethers Question 133 English Option 2
11
The major product of the following reaction is :

JEE Main 2019 (Online) 11th January Morning Slot Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 191 English
Answer
(C)
JEE Main 2019 (Online) 11th January Morning Slot Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 191 English Option 3
12
The major product of the following reaction is

JEE Main 2019 (Online) 11th January Morning Slot Chemistry - Alcohols, Phenols and Ethers Question 134 English
Answer
(B)
JEE Main 2019 (Online) 11th January Morning Slot Chemistry - Alcohols, Phenols and Ethers Question 134 English Option 2
13
Which compound (s) out of the following is/are not aromatic ?

JEE Main 2019 (Online) 11th January Morning Slot Chemistry - Hydrocarbons Question 117 English
Answer
(D)
(B), (C) and (D)
14
Among the following compounds, which one is found in RNA ?
Answer
(C)
JEE Main 2019 (Online) 11th January Morning Slot Chemistry - Biomolecules Question 137 English Option 3
15
The major product of the following reaction is :

JEE Main 2019 (Online) 11th January Morning Slot Chemistry - Compounds Containing Nitrogen Question 185 English
Answer
(C)
JEE Main 2019 (Online) 11th January Morning Slot Chemistry - Compounds Containing Nitrogen Question 185 English Option 3
16
Two blocks of the same metal having same mass and at temperature T1 and T2, respectively, are brought in contact with each other and allowed to attain thermal equilibrium at constant pressure. The change in entropy, $$\Delta $$S, for this process is :
Answer
(C)
Cp In $$\left[ {{{{{\left( {{T_1} + {T_2}} \right)}^2}} \over {4{T_1}{T_2}}}} \right]$$
17
The freezing point of a diluted milk sample is found to be –0.2oC, while it should have been –0.5oC for pure milk. How much water has been added to pure milk to make the diluted sample?
Answer
(C)
3 cups of water to 2 cups of pure milk
18
The correct match between items I and II is :

Item-I (Mixture) Item-II (Seperation method)
(A) H2O : Sugar (P) Sublimation
(B) H2O : Aniline (Q) Recrystallization
(C) H2O : Toluene
 (R) Steam distillation
(S) Differential extraction
Answer
(B)
A$$ \to $$(Q); (B)$$ \to $$(R); (C)$$ \to $$(S)
19
An organic compound is estimated through Duma's method and was found to evolve 6 moles of CO2. 4 moles of H2O and 1 mole of nitrogen gas. The formula of the compound is :
Answer
(B)
C6H8N2