All Free Chemistry MCQs with Answers

• A. Extent of a reaction
• B. Order of a reaction
• C. Specific rate of a reaction
• D. Enthalpy of reaction

Explanation: The Order of reaction refers to the relationship between the rate of a chemical reaction and the concentration of the species taking part…

• A. 2
• B. 0
• C. 1
• D. 3

Explanation: The given chemical reaction is: Rate = k[NO][O3] The order of a chemical reaction with respect to a specific reactant is determined by the…

• A. Conditions of temperature
• B. Initial Concentration of the compound
• C. Presence of Catalyst
• D. All of these

Explanation: Half-life ( t1/2t1/2 ) is a timescale on which the initial population is decreased by half of its original value notice that, for…

• A. +7
• B. +3
• C. +6
• D. +5

Explanation: a) +7:The oxidation number of iodine in periodic acid (H5IO6) is indeed +7.

• A. +1
• B. -2
• C. -1
• D. -1/2

Explanation: The explanation for this question will be added soon.

• A. Oxidation potential
• B. Reduction potential
• C. Redox potential
• D. EMF of cell

Explanation: The stronger the oxidizing agent, the greater will be its reduction potential.

• A. Anode
• B. Cathode
• C. Salt bridge
• D. None of these options are correct

Explanation: Oxidation occurs at the anode and reduction occurs at the cathode. Since the reaction at the anode is the source of electrons for the…

• A. +1
• B. +2
• C. 0
• D. -1

Explanation: Free state means uncombined state, i.e., atomic state. In an uncombined state the oxidation number will always be zero.

• A. Anode
• B. Cathode
• C. SHE
• D. Salt bridge

Explanation: Reduction happens at the negative cathode because this is where positive ions gain electrons.

• A. Anode
• B. Cathode
• C. SHE
• D. Salt bridge

Explanation: During electrolysis, reduction occurs at cathode

• A. 7
• B. -7
• C. 6
• D. -6

Explanation: The oxidation number of Mn in MnO4- can be calculated by considering the overall charge of the compound and assigning oxidation numbers to…

• A. Gain
• B. Lost
• C. Accept
• D. Produced

Explanation: The number of charges present on a cation depends on the number of electrons lost by the atom.

• A. Unity
• B. Positive
• C. Zero
• D. Negative

Explanation: Option C is correct since a free state means an 'uncombined state', i.e., atomic state.

• A. Discharged at anode
• B. Discharge at cathode
• C. Do not discharge
• D. None of these options is correct

Explanation: At Cathode Sodium is not discharged but H2 gas is discharged. Sodium remains in the solution and more H2 gas is formed at the end of…

• A. Reduction
• B. Hydrolysis
• C. Dehydration
• D. Oxidation

Explanation: K2Cr2O7 and H2SO4 lose their oxygen while acting as a reagent hence leading to the "oxidation" of the reactant. Hence, the answer will be D.

• A. Corrode slowly
• B. Does not corrode easily
• C. Corrode rapidly
• D. None of these

Explanation: Pure metals do not corrode. The absence of impurities and the ability to develop protective surface layers make pure metals less prone to…

• A. F > N > O > C
• B. F > N < O > C
• C. F < N < O < C
• D. F > N > O < C

Explanation: Fluorine is obviously the most electronegative element (4.0) followed by Oxygen (3.44), then Nitrogen(3.04) and finally Carbon(2.55).

• A. I < Br < F < Cl
• B. I < Cl < F < Br
• C. I < F < Br < Cl
• D. F < Cl < Br < I

Explanation: Option A is correct as Cl has the highest E.A in its group. Although Fluorine is expected to have the highest E.A but due to its small…

• A. I1 < I2
• B. I1 > I2
• C. I1 = I2
• D. None of these options

Explanation: Option A is correct as Successive ionization energy increases due to increasing Z.

• A. X3Y2
• B. X3Y6
• C. X2Y3
• D. None of these

Explanation: Element X will have a valency of +3 while Y will have a valency of -2. Thus the most likely formula of the compound is X2Y3.