Chemistry Syllabus (JEE Main)
Q. What is the value of the principal quantum number (n) for the outermost electrons in a sodium atom?
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Solution
Sodium has an atomic number of 11, and its electron configuration is 1s² 2s² 2p⁶ 3s¹. The outermost electrons are in n=3.
Correct Answer: C — 3
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Q. What is the value of the principal quantum number (n) for the outermost electron in a potassium atom?
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Solution
Potassium (K) has an atomic number of 19, and its electron configuration ends in 4s, so the outermost electron has n=4.
Correct Answer: C — 3
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Q. What is the value of the principal quantum number (n) for the outermost electron in potassium (K)?
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Solution
Potassium has the electronic configuration [Ar] 4s1, so the outermost electron is in n=4.
Correct Answer: B — 4
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Q. What is the value of the principal quantum number for an electron in the ground state of a hydrogen atom?
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Solution
The ground state of hydrogen corresponds to n=1.
Correct Answer: A — 1
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Q. What is the value of the principal quantum number for the outermost electrons in potassium (K)?
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Solution
Potassium has an atomic number of 19, and its outermost electrons are in the n=4 shell.
Correct Answer: D — 4
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Q. What is the value of the principal quantum number for the outermost electrons in a sodium atom?
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Solution
Sodium has an atomic number of 11, and its outermost electrons are in the n=3 shell.
Correct Answer: C — 3
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Q. What is the value of the universal gas constant R in L·atm/(K·mol)?
A.
0.0821
B.
8.314
C.
62.36
D.
1.987
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Solution
The universal gas constant R is 0.0821 L·atm/(K·mol).
Correct Answer: A — 0.0821
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Q. What is the van 't Hoff factor (i) for a strong electrolyte like NaCl in solution?
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Solution
NaCl dissociates into two ions (Na+ and Cl-), so the van 't Hoff factor (i) is 2.
Correct Answer: B — 2
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Q. What is the van 't Hoff factor (i) for a strong electrolyte that completely dissociates into 3 ions?
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Solution
The van 't Hoff factor (i) is equal to the number of particles the solute dissociates into. For a strong electrolyte that dissociates into 3 ions, i = 3.
Correct Answer: C — 3
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Q. What is the van 't Hoff factor (i) for glucose in solution?
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Solution
The van 't Hoff factor (i) for glucose is 1, as it does not dissociate in solution.
Correct Answer: A — 1
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Q. What is the van 't Hoff factor for a non-electrolyte solute?
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Solution
For a non-electrolyte solute, the van 't Hoff factor (i) is 1, as it does not dissociate into ions.
Correct Answer: B — 1
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Q. What is the vapor pressure of a solution containing 0.1 mol of a non-volatile solute in 1 kg of water? (Vapor pressure of pure water = 23.76 mmHg)
A.
22.88 mmHg
B.
21.76 mmHg
C.
20.76 mmHg
D.
19.76 mmHg
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Solution
Vapor pressure = P°_solvent * (n_solvent / (n_solvent + n_solute)) = 23.76 * (55.5 / (55.5 + 0.1)) = 22.88 mmHg
Correct Answer: A — 22.88 mmHg
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Q. What is the vapor pressure of a solution containing 1 mole of a non-volatile solute in 10 moles of solvent, assuming ideal behavior?
A.
0.1 P0
B.
0.9 P0
C.
1.0 P0
D.
0.5 P0
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Solution
Using Raoult's law, the vapor pressure of the solution = (moles of solvent / total moles) * P0 = (10 / 11) * P0 = 0.909 P0.
Correct Answer: B — 0.9 P0
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Q. What is the vapor pressure of a solution containing 1 mole of a non-volatile solute in 3 moles of solvent, assuming ideal behavior?
A.
0.25 P0
B.
0.75 P0
C.
1.0 P0
D.
0.5 P0
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Solution
Vapor pressure lowering = (moles of solute / total moles) * P0 = (1 / (1 + 3)) * P0 = 0.25 P0, so vapor pressure = P0 - 0.25 P0 = 0.75 P0.
Correct Answer: B — 0.75 P0
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Q. What is the vapor pressure of a solution containing 1 mole of a non-volatile solute in 9 moles of solvent, if the vapor pressure of the pure solvent is 100 mmHg?
A.
90 mmHg
B.
100 mmHg
C.
10 mmHg
D.
80 mmHg
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Solution
Using Raoult's law, P_solution = X_solvent * P°_solvent = (9/10) * 100 mmHg = 90 mmHg.
Correct Answer: A — 90 mmHg
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Q. What is the vapor pressure of a solution containing 1 mole of non-volatile solute in 3 moles of solvent if the vapor pressure of the pure solvent is 100 mmHg?
A.
75 mmHg
B.
100 mmHg
C.
25 mmHg
D.
50 mmHg
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Solution
Using Raoult's law, P_solution = X_solvent * P°_solvent. X_solvent = 3/(1+3) = 0.75, so P_solution = 0.75 * 100 mmHg = 75 mmHg.
Correct Answer: A — 75 mmHg
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Q. What is the vapor pressure of a solution containing 1 mole of solute in 3 moles of solvent, assuming ideal behavior?
A.
0.25 P0
B.
0.75 P0
C.
0.5 P0
D.
P0
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Solution
Using Raoult's law, the vapor pressure of the solution = (moles of solvent / total moles) * P0 = (3 / (3 + 1)) * P0 = 0.75 P0.
Correct Answer: B — 0.75 P0
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Q. What is the vapor pressure of a solution containing a non-volatile solute compared to the pure solvent?
A.
Higher than the pure solvent
B.
Lower than the pure solvent
C.
Equal to the pure solvent
D.
Unpredictable
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Solution
The vapor pressure of a solution containing a non-volatile solute is lower than that of the pure solvent due to the presence of solute particles.
Correct Answer: B — Lower than the pure solvent
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Q. What is the volume occupied by 1 mole of an ideal gas at STP (Standard Temperature and Pressure)?
A.
22.4 L
B.
24.0 L
C.
18.0 L
D.
20.0 L
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Solution
At STP, 1 mole of an ideal gas occupies 22.4 liters.
Correct Answer: A — 22.4 L
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Q. What is the volume occupied by 1 mole of an ideal gas at STP?
A.
22.4 L
B.
24 L
C.
20 L
D.
18 L
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Solution
At STP, 1 mole of an ideal gas occupies 22.4 liters.
Correct Answer: A — 22.4 L
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Q. What is the volume occupied by 4 moles of an ideal gas at STP?
A.
22.4 L
B.
44.8 L
C.
67.2 L
D.
89.6 L
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Solution
At STP, 1 mole of gas occupies 22.4 L. Therefore, 4 moles occupy 4 x 22.4 L = 89.6 L.
Correct Answer: B — 44.8 L
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Q. What is the volume of 1 M NaOH solution required to obtain 0.5 moles of NaOH?
A.
0.5 L
B.
1 L
C.
2 L
D.
0.25 L
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Solution
Using the formula M = moles/volume, Volume = moles/M = 0.5 moles / 1 M = 0.5 L.
Correct Answer: A — 0.5 L
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Q. What is the volume of 1 mole of an ideal gas at STP (Standard Temperature and Pressure)?
A.
22.4 L
B.
24.0 L
C.
18.0 L
D.
20.0 L
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Solution
At STP, 1 mole of an ideal gas occupies 22.4 liters.
Correct Answer: A — 22.4 L
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Q. What is the volume of 1 mole of an ideal gas at STP?
A.
22.4 L
B.
24 L
C.
10 L
D.
1 L
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Solution
At STP (Standard Temperature and Pressure), 1 mole of an ideal gas occupies 22.4 liters.
Correct Answer: A — 22.4 L
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Q. What is the volume of 4 moles of an ideal gas at STP?
A.
22.4 L
B.
44.8 L
C.
89.6 L
D.
112 L
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Solution
Volume = moles x volume per mole = 4 moles x 22.4 L/mole = 89.6 L.
Correct Answer: C — 89.6 L
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Q. What is the volume of a 2 M solution that contains 4 moles of solute?
A.
2 L
B.
4 L
C.
1 L
D.
0.5 L
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Solution
Volume = moles of solute / molarity = 4 moles / 2 M = 2 L.
Correct Answer: B — 4 L
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Q. What is the volume of CO2 produced at STP when 2 moles of C2H5OH are completely combusted?
A.
22.4 L
B.
44.8 L
C.
67.2 L
D.
89.6 L
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Solution
C2H5OH + 3O2 → 2CO2 + 3H2O. 2 moles of C2H5OH produce 4 moles of CO2. Volume = 4 * 22.4 L = 89.6 L.
Correct Answer: B — 44.8 L
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Q. What is the volume percent concentration of a solution containing 30 mL of ethanol in 150 mL of solution?
A.
20%
B.
25%
C.
30%
D.
15%
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Solution
Volume percent = (volume of solute / total volume) x 100 = (30 mL / 150 mL) x 100 = 20%.
Correct Answer: B — 25%
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Q. What is the volume percent of ethanol in a solution made by mixing 30 mL of ethanol with 70 mL of water?
A.
30%
B.
70%
C.
50%
D.
20%
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Solution
Volume percent = (volume of solute / total volume) × 100 = (30 mL / (30 mL + 70 mL)) × 100 = 30%.
Correct Answer: A — 30%
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Q. What is the work done by a gas during an isothermal expansion from volume Vi to Vf?
A.
nRT ln(Vf/Vi)
B.
nR(Tf - Ti)
C.
Zero
D.
nRT
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Solution
The work done by a gas during an isothermal expansion is W = nRT ln(Vf/Vi).
Correct Answer: A — nRT ln(Vf/Vi)
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