Chemistry
Q. What is the change in internal energy of an ideal gas when it is heated at constant volume? (2021) 2021
A.
Zero
B.
Equal to heat added
C.
Equal to work done
D.
Equal to pressure times volume
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Solution
At constant volume, the change in internal energy (ΔU) is equal to the heat added (Q). Therefore, ΔU = Q.
Correct Answer: B — Equal to heat added
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Q. What is the chemical formula for sodium chloride? (2023) 2023
A.
NaCl
B.
Na2Cl
C.
NaCl2
D.
Na2Cl2
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Solution
The chemical formula for sodium chloride is NaCl.
Correct Answer: A — NaCl
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Q. What is the chemical formula for table salt? (2019)
A.
NaCl
B.
KCl
C.
CaCl2
D.
MgCl2
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Solution
Table salt is chemically known as sodium chloride, which has the formula NaCl.
Correct Answer: A — NaCl
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Q. What is the color of the complex [Cu(H2O)6]2+? (2023) 2023
A.
Green
B.
Blue
C.
Red
D.
Yellow
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Solution
[Cu(H2O)6]2+ is typically blue due to the d-d transitions of the copper ion in an octahedral field.
Correct Answer: B — Blue
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Q. What is the common oxidation state of Alkaline earth metals? (2014) 2014
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Solution
Alkaline earth metals commonly exhibit a +2 oxidation state.
Correct Answer: B — +2
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Q. What is the common oxidation state of Group 1 elements? (2021)
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Solution
Group 1 elements commonly exhibit an oxidation state of +1.
Correct Answer: C — +1
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Q. What is the common oxidation state of Group 13 elements? (2021)
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Solution
Group 13 elements commonly exhibit a +3 oxidation state due to the loss of three valence electrons.
Correct Answer: C — +3
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Q. What is the common oxidation state of nitrogen in ammonia (NH3)? (2023) 2023
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Solution
In ammonia (NH3), nitrogen has an oxidation state of -3.
Correct Answer: A — -3
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Q. What is the concentration in mol/L of a solution made by dissolving 58.5 grams of NaCl in 1 liter of water? (Molar mass of NaCl = 58.5 g/mol) (2023) 2023
A.
1 M
B.
0.5 M
C.
2 M
D.
0.25 M
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Solution
Moles of NaCl = 58.5 g / 58.5 g/mol = 1 mole. Molarity = 1 mole / 1 L = 1 M.
Correct Answer: A — 1 M
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Q. What is the concentration of a solution if 5 g of NaOH is dissolved in 250 mL of water? (2020)
A.
0.5 M
B.
1 M
C.
0.2 M
D.
0.1 M
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Solution
Moles of NaOH = 5 g / 40 g/mol = 0.125 mol. Molarity = 0.125 mol / 0.25 L = 0.5 M.
Correct Answer: B — 1 M
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Q. What is the concentration of H+ ions in a solution with pH 3? (2019) 2019
A.
0.001 M
B.
0.01 M
C.
0.1 M
D.
1 M
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Solution
Concentration of H+ = 10^(-pH) = 10^(-3) = 0.001 M.
Correct Answer: B — 0.01 M
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Q. What is the concentration of H+ ions in a solution with pH 4?
A.
0.0001 M
B.
0.01 M
C.
0.1 M
D.
1 M
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Solution
[H+] = 10^(-pH) = 10^(-4) = 0.0001 M.
Correct Answer: A — 0.0001 M
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Q. What is the coordination number of the central metal ion in the complex ion [Co(NH3)6]Cl3? (2021)
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Solution
In the complex ion [Co(NH3)6]Cl3, the central metal ion Co is surrounded by 6 ammonia (NH3) ligands, which gives it a coordination number of 6.
Correct Answer: C — 6
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Q. What is the coordination number of the complex ion [Co(NH3)5Cl]Cl2? (2023)
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Solution
In the complex [Co(NH3)5Cl]Cl2, cobalt is surrounded by five ammonia ligands and one chloride ligand, giving it a coordination number of 6.
Correct Answer: C — 6
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Q. What is the coordination number of the complex ion [Co(NH3)6]Cl3? (2022) 2022
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Solution
The coordination number is determined by the number of ligands attached to the central metal ion. Here, Co is surrounded by 6 NH3 ligands.
Correct Answer: B — 6
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Q. What is the coordination number of the metal ion in the complex [Co(NH3)5Cl]Cl2? (2023)
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Solution
In the complex [Co(NH3)5Cl]Cl2, cobalt is surrounded by five ammonia ligands and one chloride ligand, giving it a coordination number of 6.
Correct Answer: C — 6
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Q. What is the effect of adding a common ion on the solubility of a salt? (2020)
A.
Increases solubility
B.
Decreases solubility
C.
No effect
D.
Depends on temperature
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Solution
Adding a common ion decreases the solubility of a salt due to the common ion effect, which shifts the equilibrium to the left.
Correct Answer: B — Decreases solubility
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Q. What is the effect of increasing pressure on a gas at constant temperature? (2014)
A.
Volume increases
B.
Volume decreases
C.
No effect on volume
D.
Gas becomes a liquid
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Solution
According to Boyle's Law, increasing pressure on a gas at constant temperature results in a decrease in volume.
Correct Answer: B — Volume decreases
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Q. What is the effect of increasing temperature on chemisorption? (2022)
A.
Increases adsorption
B.
Decreases adsorption
C.
No effect
D.
Depends on the gas
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Solution
Chemisorption is an exothermic process, and increasing temperature generally decreases the extent of chemisorption.
Correct Answer: B — Decreases adsorption
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Q. What is the effect of increasing temperature on the volume of a gas at constant pressure?
A.
Volume decreases
B.
Volume increases
C.
Volume remains constant
D.
Volume fluctuates
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Solution
According to Charles's Law, increasing the temperature of a gas at constant pressure increases its volume.
Correct Answer: B — Volume increases
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Q. What is the effect of increasing the temperature on the solubility of most solid solutes in water? (2023)
A.
Increases solubility
B.
Decreases solubility
C.
No effect
D.
Depends on the solute
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Solution
For most solid solutes, increasing the temperature increases their solubility in water.
Correct Answer: A — Increases solubility
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Q. What is the effect of temperature on chemisorption? (2023)
A.
Increases with temperature
B.
Decreases with temperature
C.
Remains constant
D.
Depends on the gas
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Solution
Chemisorption typically decreases with an increase in temperature because it involves the formation of stronger chemical bonds, which are less favorable at higher thermal energies.
Correct Answer: B — Decreases with temperature
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Q. What is the effect of temperature on chemisorption? (2023) 2023
A.
Increases with temperature
B.
Decreases with temperature
C.
Remains constant
D.
Depends on the gas
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Solution
Chemisorption typically decreases with an increase in temperature because it involves the formation of stronger chemical bonds, which are less favorable at higher thermal energies.
Correct Answer: B — Decreases with temperature
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Q. What is the effect of temperature on the cell potential according to the Nernst equation?
A.
Increases with temperature
B.
Decreases with temperature
C.
No effect
D.
Depends on the reaction
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Solution
According to the Nernst equation, the cell potential generally increases with temperature.
Correct Answer: A — Increases with temperature
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Q. What is the efficiency of a Carnot engine operating between temperatures T1 and T2? (2019) 2019
A.
(T1 - T2) / T1
B.
T2 / T1
C.
(T1 - T2) / T2
D.
1 - (T2 / T1)
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Solution
The efficiency (η) of a Carnot engine is given by η = 1 - (T2 / T1), where T1 is the higher temperature and T2 is the lower temperature.
Correct Answer: D — 1 - (T2 / T1)
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Q. What is the electron configuration of Chromium?
A.
[Ar] 3d4 4s2
B.
[Ar] 3d5 4s1
C.
[Ar] 3d6 4s2
D.
[Ar] 3d3 4s2
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Solution
Chromium (Cr) has the electron configuration [Ar] 3d5 4s1 due to stability of half-filled d-orbitals.
Correct Answer: B — [Ar] 3d5 4s1
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Q. What is the equilibrium constant (K) for the dissociation of acetic acid (CH3COOH) in water? (2023)
A.
1.8 x 10^-5
B.
1.0
C.
10
D.
100
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Solution
The dissociation constant (K) for acetic acid is approximately 1.8 x 10^-5, indicating it is a weak acid.
Correct Answer: A — 1.8 x 10^-5
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Q. What is the equilibrium constant (Kc) for the reaction 2A + B ⇌ C? (2022)
A.
Kc = [C] / ([A]^2[B])
B.
Kc = [A]^2[B] / [C]
C.
Kc = [B] / ([A]^2[C])
D.
Kc = [C] / ([B][A])
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Solution
The equilibrium constant Kc is defined as the concentration of the products raised to the power of their coefficients divided by the concentration of the reactants raised to the power of their coefficients. For the reaction 2A + B ⇌ C, Kc = [C] / ([A]^2[B]).
Correct Answer: A — Kc = [C] / ([A]^2[B])
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Q. What is the equilibrium constant (Kc) for the reaction: A + B ⇌ C + D? (2022)
A.
Kc = [C][D]/[A][B]
B.
Kc = [A][B]/[C][D]
C.
Kc = [C][D][A][B]
D.
Kc = [A][B][C][D]
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Solution
The equilibrium constant Kc is defined as the ratio of the concentrations of the products to the reactants, each raised to the power of their coefficients in the balanced equation.
Correct Answer: A — Kc = [C][D]/[A][B]
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Q. What is the equilibrium constant (Kc) for the reaction: N2(g) + 3H2(g) ⇌ 2NH3(g)? (2022) 2022
A.
1.0 × 10^-5
B.
1.0 × 10^-2
C.
1.0 × 10^2
D.
1.0 × 10^5
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Solution
The equilibrium constant Kc for the formation of ammonia from nitrogen and hydrogen is typically around 1.0 × 10^5 at standard conditions.
Correct Answer: D — 1.0 × 10^5
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