Q. What is the bond angle in a tetrahedral molecule?
A.90 degrees
B.120 degrees
C.109.5 degrees
D.180 degrees
Solution
In a tetrahedral geometry, the bond angles are approximately 109.5 degrees.
Correct Answer: C — 109.5 degrees
Q. What is the bond angle in a trigonal planar molecule?
A.120 degrees
B.109.5 degrees
C.180 degrees
D.90 degrees
Solution
In a trigonal planar geometry, the bond angles are 120 degrees.
Correct Answer: A — 120 degrees
Q. What is the bond angle in a water molecule (H2O)?
A.120 degrees
B.109.5 degrees
C.104.5 degrees
D.180 degrees
Solution
The bond angle in H2O is approximately 104.5 degrees due to the two lone pairs on oxygen.
Correct Answer: C — 104.5 degrees
Q. What is the bond angle in water (H2O)?
A.90 degrees
B.104.5 degrees
C.120 degrees
D.180 degrees
Solution
The bond angle in water (H2O) is approximately 104.5 degrees.
Correct Answer: B — 104.5 degrees
Q. What is the bond order of the ion O2-?
A.1
B.2
C.3
D.4
Solution
O2- has a bond order of 1, calculated as (10 bonding electrons - 7 antibonding electrons)/2 = 1.
Correct Answer: B — 2
Q. What is the bond order of the molecule CO?
A.1
B.2
C.3
D.0.5
Solution
CO has a bond order of 3, calculated as (10 bonding electrons - 2 antibonding electrons)/2 = 3.
Correct Answer: C — 3
Q. What is the change in enthalpy for an endothermic reaction?
A.Negative
B.Positive
C.Zero
D.Undefined
Solution
In an endothermic reaction, heat is absorbed from the surroundings, resulting in a positive change in enthalpy.
Correct Answer: B — Positive
Q. What is the change in enthalpy for an exothermic reaction?
A.Positive
B.Negative
C.Zero
D.Undefined
Solution
In an exothermic reaction, heat is released, resulting in a negative change in enthalpy.
Correct Answer: B — Negative
Q. What is the change in enthalpy for an isothermal process?
A.Zero
B.Positive
C.Negative
D.Depends on the system
Solution
In an isothermal process, the temperature remains constant, and for an ideal gas, the change in enthalpy is zero.
Correct Answer: A — Zero
Q. What is the change in entropy when 1 mole of an ideal gas expands isothermally and reversibly from volume V1 to V2?
A.R ln(V2/V1)
B.R (V2 - V1)
C.R (V1/V2)
D.0
Solution
The change in entropy for an isothermal and reversible expansion of an ideal gas is given by ΔS = nR ln(V2/V1). For 1 mole, n = 1, hence ΔS = R ln(V2/V1).
Correct Answer: A — R ln(V2/V1)
Q. What is the change in oxidation state of carbon in the reaction: CH4 + 2O2 → CO2 + 2H2O?
A.0 to +4
B.+4 to 0
C.0 to -4
D.-4 to 0
Solution
The oxidation state of carbon changes from -4 in CH4 to +4 in CO2.
Correct Answer: A — 0 to +4
Q. What is the color of the complex ion [Cu(H2O)6]2+?
A.Blue
B.Green
C.Yellow
D.Red
Solution
The complex ion [Cu(H2O)6]2+ is blue due to d-d transitions.
Correct Answer: A — Blue
Q. What is the color of the complex [Cu(H2O)6]2+?
A.Blue
B.Green
C.Red
D.Yellow
Solution
[Cu(H2O)6]2+ is known to exhibit a blue color due to d-d transitions in the presence of water ligands.
Correct Answer: A — Blue
Q. What is the common oxidation state of actinides in their compounds?
A.+3
B.+4
C.+5
D.+6
Solution
The common oxidation state of actinides in their compounds is +4.
Correct Answer: D — +6
Q. What is the common oxidation state of alkali metals?
A.+1
B.+2
C.0
D.-1
Solution
Alkali metals have a common oxidation state of +1.
Correct Answer: A — +1
Q. What is the common oxidation state of Chromium in chromates?
A.+2
B.+3
C.+4
D.+6
Solution
Chromium commonly exhibits a +6 oxidation state in chromates (CrO4^2-).
Correct Answer: D — +6
Q. What is the common oxidation state of Chromium in its compounds?
A.+2
B.+3
C.+6
D.+5
Solution
Chromium commonly exhibits a +6 oxidation state in compounds such as chromium trioxide (CrO3).
Correct Answer: C — +6
Q. What is the common oxidation state of nitrogen in ammonia (NH3)?
A.-3
B.0
C.+1
D.+3
Solution
In ammonia, nitrogen has an oxidation state of -3.
Correct Answer: A — -3
Q. What is the concentration in g/L of a solution containing 0.5 moles of KCl in 1.5 L of solution? (Molar mass of KCl = 74.5 g/mol)
A.24.83 g/L
B.49.67 g/L
C.37.25 g/L
D.50 g/L
Solution
Mass of KCl = 0.5 moles × 74.5 g/mol = 37.25 g. Concentration = 37.25 g / 1.5 L = 24.83 g/L.
Correct Answer: B — 49.67 g/L
Q. What is the concentration in molality of a solution made by dissolving 5 moles of solute in 3 kg of solvent?
A.1.67 m
B.2 m
C.1.5 m
D.2.5 m
Solution
Molality (m) = moles of solute / kg of solvent = 5 moles / 3 kg = 1.67 m.
Correct Answer: B — 2 m
Q. What is the concentration in molarity of a solution that contains 0.5 moles of solute in 1.5 liters of solution?
A.0.33 M
B.0.5 M
C.0.75 M
D.1 M
Solution
Molarity (M) = moles of solute / liters of solution = 0.5 moles / 1.5 L = 0.33 M.
Correct Answer: C — 0.75 M
Q. What is the concentration of a solution if 10 grams of NaCl is dissolved in 500 mL of water? (Molar mass of NaCl = 58.5 g/mol)
A.0.34 M
B.0.17 M
C.0.50 M
D.0.25 M
Solution
Molarity (M) = moles of solute / liters of solution = (10 g / 58.5 g/mol) / 0.5 L = 0.34 M.
Correct Answer: A — 0.34 M
Q. What is the coordination number of the central metal ion in [Co(NH3)6]Cl3?
A.2
B.4
C.6
D.8
Solution
The coordination number of the central metal ion (Co) in [Co(NH3)6]Cl3 is 6.
Correct Answer: C — 6
Q. What is the critical temperature of a gas?
A.The temperature above which a gas cannot be liquefied
B.The temperature at which a gas condenses
C.The temperature at which a gas expands
D.The temperature at which a gas is at its maximum density
Solution
The critical temperature is the temperature above which a gas cannot be liquefied, regardless of the pressure applied.
Correct Answer: A — The temperature above which a gas cannot be liquefied
Q. What is the critical temperature of a substance?
A.The temperature at which a substance boils
B.The temperature above which a gas cannot be liquefied
C.The temperature at which a substance freezes
D.The temperature at which a substance condenses
Solution
The critical temperature is the temperature above which a gas cannot be liquefied.
Correct Answer: B — The temperature above which a gas cannot be liquefied
Q. What is the effect of a -CH3 group on the stability of a carbocation?
A.Destabilizes
B.No effect
C.Stabilizes
D.Increases acidity
Solution
The -CH3 group is an electron-donating group and stabilizes the carbocation through hyperconjugation.
Correct Answer: C — Stabilizes
Q. What is the effect of a -I group on the acidity of a carboxylic acid?
A.Increases acidity
B.Decreases acidity
C.No effect
D.Only affects basicity
Solution
A -I group increases the acidity of a carboxylic acid by stabilizing the negative charge on the conjugate base.
Correct Answer: A — Increases acidity
Q. What is the effect of a -I group on the acidity of carboxylic acids?
A.Increases acidity
B.Decreases acidity
C.No effect
D.Depends on the solvent
Solution
A -I group increases the acidity of carboxylic acids by stabilizing the negative charge on the conjugate base.
Correct Answer: A — Increases acidity
Q. What is the effect of a catalyst on the equilibrium position of a reversible reaction?
A.Shifts the equilibrium to the right
B.Shifts the equilibrium to the left
C.No effect on equilibrium position
D.Increases the equilibrium constant
Solution
A catalyst does not affect the position of equilibrium; it only speeds up the rate at which equilibrium is reached.
Correct Answer: C — No effect on equilibrium position
Q. What is the effect of a non-volatile solute on the boiling point of a solvent?
A.It decreases the boiling point
B.It increases the boiling point
C.It has no effect
D.It changes the boiling point unpredictably
Solution
The addition of a non-volatile solute raises the boiling point of the solvent, a phenomenon known as boiling point elevation.
Correct Answer: B — It increases the boiling point
