Chemistry Syllabus (JEE Main)
Q. In the reaction 4Fe + 3O2 → 2Fe2O3, how many grams of Fe2O3 can be produced from 8 grams of Fe?
A.
16 g
B.
32 g
C.
48 g
D.
24 g
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Solution
8 g of Fe = 0.143 moles. 4 moles of Fe produce 2 moles of Fe2O3, so 0.0715 moles of Fe2O3 = 0.0715 * 160 g = 11.44 g.
Correct Answer: C — 48 g
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Q. In the reaction 4Fe + 3O2 → 2Fe2O3, how many moles of Fe are required to react with 6 moles of O2?
A.
4 moles
B.
6 moles
C.
8 moles
D.
12 moles
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Solution
From the balanced equation, 3 moles of O2 react with 4 moles of Fe. Therefore, 6 moles of O2 will require (4/3) * 6 = 8 moles of Fe.
Correct Answer: C — 8 moles
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Q. In the reaction 4Fe + 3O2 → 2Fe2O3, how many moles of Fe2O3 are produced from 12 moles of Fe?
A.
2 moles
B.
3 moles
C.
4 moles
D.
6 moles
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Solution
From the balanced equation, 4 moles of Fe produce 2 moles of Fe2O3. Therefore, 12 moles of Fe will produce (12/4) x 2 = 6 moles of Fe2O3.
Correct Answer: C — 4 moles
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Q. In the reaction 4Fe + 3O2 → 2Fe2O3, how many moles of Fe2O3 can be produced from 12 moles of Fe?
A.
3 moles
B.
6 moles
C.
9 moles
D.
12 moles
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Solution
From the stoichiometry, 4 moles of Fe produce 2 moles of Fe2O3. Therefore, 12 moles of Fe will produce (12/4) x 2 = 6 moles of Fe2O3.
Correct Answer: B — 6 moles
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Q. In the reaction 4Fe + 3O2 → 2Fe2O3, what is the oxidation state of iron in Fe2O3?
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Solution
In Fe2O3, iron has an oxidation state of +3.
Correct Answer: B — +3
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Q. In the reaction CO(g) + 2H2(g) ⇌ CH3OH(g), if the pressure is increased, which direction will the equilibrium shift?
A.
To the left
B.
To the right
C.
No shift
D.
Depends on temperature
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Solution
Increasing pressure shifts the equilibrium towards the side with fewer moles of gas, which is the right side in this case.
Correct Answer: B — To the right
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Q. In the reaction CO(g) + 2H2(g) ⇌ CH3OH(g), what will happen if H2 is removed from the system at equilibrium?
A.
Equilibrium shifts to the right
B.
Equilibrium shifts to the left
C.
No change
D.
Equilibrium constant increases
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Solution
Removing H2 will shift the equilibrium to the left to produce more H2, thus favoring the reactants.
Correct Answer: B — Equilibrium shifts to the left
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Q. In the reaction CO(g) + 2H2(g) ⇌ CH3OH(g), what will happen if H2 is removed from the system?
A.
Shift to the left
B.
Shift to the right
C.
No change
D.
Increase the rate of reaction
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Solution
Removing H2 will shift the equilibrium to the left to produce more H2, according to Le Chatelier's principle.
Correct Answer: A — Shift to the left
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Q. In the reaction CO(g) + 2H2(g) ⇌ CH3OH(g), what will happen if H2 is removed?
A.
Shift to the right
B.
Shift to the left
C.
No change
D.
Equilibrium constant increases
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Solution
Removing H2 will shift the equilibrium to the left to produce more H2, according to Le Chatelier's principle.
Correct Answer: B — Shift to the left
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Q. In the reaction CO(g) + 2H2(g) ⇌ CH3OH(g), what will happen if the volume of the container is decreased?
A.
Shift to the right
B.
Shift to the left
C.
No change
D.
Increase in temperature
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Solution
Decreasing the volume increases the pressure, which shifts the equilibrium to the side with fewer moles of gas, favoring the production of CH3OH.
Correct Answer: A — Shift to the right
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Q. In the reaction: 2A(g) ⇌ B(g) + C(g), if the volume of the container is decreased, what will happen?
A.
Shift to the left
B.
Shift to the right
C.
No change
D.
Depends on the temperature
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Solution
Decreasing the volume increases the pressure, and the equilibrium will shift towards the side with fewer moles of gas, which is the left side in this case.
Correct Answer: A — Shift to the left
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Q. In the reaction: 2A(g) ⇌ B(g) + C(g), if the volume of the container is decreased, what will happen to the equilibrium?
A.
Shift to the left
B.
Shift to the right
C.
No change
D.
Depends on temperature
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Solution
Decreasing the volume increases the pressure, and the equilibrium will shift to the side with fewer moles of gas, which is the left side in this case.
Correct Answer: A — Shift to the left
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Q. In the reaction: 2SO2(g) + O2(g) ⇌ 2SO3(g), what happens if the temperature is increased?
A.
Shift to the right
B.
Shift to the left
C.
No change
D.
Increase in Kp
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Solution
If the reaction is exothermic, increasing the temperature will shift the equilibrium to the left, favoring the reactants.
Correct Answer: B — Shift to the left
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Q. In the redox reaction 2Fe2O3 + 3C → 4Fe + 3CO2, what is the oxidation state of carbon in CO2?
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Solution
In CO2, the oxidation state of carbon is +4.
Correct Answer: C — +4
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Q. In the van der Waals equation, what do the constants 'a' and 'b' represent?
A.
Pressure and volume
B.
Attraction and volume
C.
Temperature and pressure
D.
Volume and temperature
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Solution
'a' accounts for the attractive forces between molecules, while 'b' accounts for the volume occupied by the gas molecules.
Correct Answer: B — Attraction and volume
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Q. In thermodynamics, what does the term 'enthalpy' refer to?
A.
Internal energy plus pressure times volume
B.
Internal energy minus pressure times volume
C.
Heat content of a system
D.
Work done by a system
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Solution
Enthalpy is defined as H = U + PV, where U is internal energy, P is pressure, and V is volume.
Correct Answer: A — Internal energy plus pressure times volume
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Q. In which of the following cases does the mesomeric effect dominate over the inductive effect?
A.
Aromatic compounds
B.
Aliphatic compounds
C.
Alkynes
D.
Alkenes
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Solution
In aromatic compounds, the mesomeric effect dominates due to resonance stabilization.
Correct Answer: A — Aromatic compounds
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Q. In which of the following compounds does the central atom exhibit dsp3 hybridization?
A.
PCl5
B.
SF6
C.
XeF4
D.
NH3
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Solution
In PCl5, phosphorus exhibits dsp3 hybridization, forming five P-Cl bonds.
Correct Answer: A — PCl5
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Q. In which of the following compounds does the central atom exhibit sp hybridization?
A.
C2H4
B.
N2
C.
HCl
D.
C2H2
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Solution
In C2H2, the carbon atoms are sp hybridized, forming a triple bond between them.
Correct Answer: D — C2H2
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Q. In which of the following compounds does the central atom have sp3d hybridization?
A.
PCl5
B.
SiCl4
C.
XeF4
D.
NH4Cl
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Solution
In PCl5, the phosphorus atom is sp3d hybridized, allowing it to form five P-Cl bonds.
Correct Answer: A — PCl5
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Q. In which of the following compounds does the inductive effect play a significant role?
A.
Benzene
B.
Acetic acid
C.
Cyclohexane
D.
Ethylene
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Solution
In acetic acid, the inductive effect of the –COOH group influences the acidity of the compound.
Correct Answer: B — Acetic acid
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Q. In which of the following compounds is the bond order equal to 1?
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Solution
H2 has a bond order of 1, indicating a single bond between the two hydrogen atoms.
Correct Answer: C — H2
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Q. In which of the following conditions does a gas deviate most from ideal behavior?
A.
High temperature and low pressure
B.
Low temperature and high pressure
C.
High temperature and high pressure
D.
Low temperature and low pressure
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Solution
A gas deviates most from ideal behavior at low temperatures and high pressures due to increased intermolecular forces.
Correct Answer: B — Low temperature and high pressure
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Q. In which of the following molecules does the molecular orbital configuration lead to paramagnetism?
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Solution
O2 is paramagnetic due to the presence of two unpaired electrons in its molecular orbitals.
Correct Answer: B — O2
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Q. In which of the following molecules does the molecular orbital configuration show unpaired electrons?
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Solution
O2 has two unpaired electrons in its π* orbitals, making it paramagnetic.
Correct Answer: B — O2
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Q. In which of the following molecules does the molecular orbital diagram show a paramagnetic behavior?
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Solution
O2 is paramagnetic due to the presence of two unpaired electrons in its molecular orbitals.
Correct Answer: B — O2
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Q. In which of the following molecules does the molecular orbital theory predict a paramagnetic behavior?
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Solution
O2 is paramagnetic due to the presence of two unpaired electrons in its molecular orbitals.
Correct Answer: B — O2
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Q. In which of the following molecules does the molecular orbital theory predict a triple bond?
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Solution
N2 has a triple bond, with a bond order of 3 according to molecular orbital theory.
Correct Answer: A — N2
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Q. In which of the following orbitals would an electron have the highest energy?
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Solution
The 3s orbital has the highest principal quantum number (n=3), indicating it has the highest energy.
Correct Answer: D — 3s
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Q. In which of the following reactions is the enthalpy change likely to be the largest?
A.
Dissolving salt in water
B.
Combustion of gasoline
C.
Melting of ice
D.
Sublimation of dry ice
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Solution
The combustion of gasoline releases a large amount of energy, resulting in a large enthalpy change.
Correct Answer: B — Combustion of gasoline
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