All Free Chemistry MCQs with Answers

• A. Emf(oxidation) - Emf(reduction)
• B. Emf(oxidation) + Emf(reduction)
• C. Emf(oxidation) x Emf(reduction)
• D. None of these options are correct

Explanation: This formula is present in the book:Emf of a cell = Oxidation Potential of Anode - Reduction Potential of Cathode.

• A. 2atm
• B. 780 mmHg
• C. 19 Psi
• D. 1 atm

Explanation: To setup a standard half-cell, the conditions are 298.15 Kelvin (temperature), 1 atmosphere (pressure), and have a Molarity of 1.0 M for…

• A. 273.16 K and 1 atm
• B. 0oC & 1 mm Hg
• C. 273.16oC & 1 atm
• D. 0 K & 1 atm

Explanation: The standard temperature and pressure are 273.16K (0oC) and 1 atm. All the remaining options are incorrect.

• A. 2.24 dm3
• B. 6.44 dm3
• C. 1.12 dm3
• D. 112 dm3

Explanation: First, we find out the number of moles using the formula moles = mass/MrMr of nitrogen will be 14+14 = 28So 8/28 = 0.28Then we use volume…

• A. Atm
• B. Pascal
• C. mm of Hg
• D. Millibar

Explanation: Correct option is D. Meteorologists use a metric unit for pressure called a millibar.

• A. Destructive distillation
• B. Fractional distillation
• C. Vacuum distillation
• D. Partial distillation

Explanation: Destructive distillation is a process that involves heating organic material in the absence of air or oxygen to break it down into simpler…

• A. Coal tar
• B. Coke
• C. Coal gas
• D. All of above

Explanation: Destructive distillation is a chemical process in which decomposition is achieved by heating to a high temperature; the term generally…

• A. Crystallization
• B. Distillation
• C. Re-distillation
• D. Fractional distillation

Explanation: c) Re-distillation: Re-distillation is essentially the same as distillation.

• A. 290°C
• B. 110°C
• C. 156°C
• D. 210°C

Explanation: Correct option is D. Under vacuum, the boiling temperature of glycerin decreases to 210°C at 50 torr.

• A. Rate constant
• B. Enthalpy
• C. Temperature
• D. Yield

Explanation: The rate of reaction can be determined by a number of methods, including physical and chemical methods.

• A. Percentage
• B. Actual
• C. Theoretical
• D. Combination of all of these

Explanation: The actual yield is obtained from the reaction. Theoretical yield is calculated from a balanced chemical equation.

• A. Percentage
• B. Actual
• C. Theoretical
• D. All of these options are correct

Explanation: The efficiency of a chemical reaction is determined by the percentage yield, that is the ratio of theoretical yield to actual yield…

• A. System
• B. Surroundings
• C. Boundary
• D. None of these options are correct

Explanation: The substance within the cylinder is the system and cylinder itself, piston and everything outside the cylinder is a part of the…

• A. Amount of heat added to the system
• B. Amount of heat rejected from the system
• C. Temperature of the substance
• D. Amount of the substance

Explanation: Enthalpy change is a state function so it does not depend on the path taken by the reaction.

• A. 4.18 J/g/0C
• B. 9.82 J/g/0C
• C. 6.04 J/g/0C
• D. 8.47 J/g/0C

Explanation: Water's specific heat power is 4.2 joules per gram per Celsius degree or 1 calorie per gram per Celsius degree.

• A. 4.184J
• B. 4.184 kJ
• C. 0.4184J
• D. 0.4184kJ

Explanation: Since 1925 this calorie has been defined in terms of the joule, the definition since 1948 being that one calorie is equal to approximately…

• A. Pressure (P)
• B. Work(W)
• C. Volume (V)
• D. Temperature (T)

Explanation: Work is not an state function. It is a pathway function

• A. Surrounding
• B. System
• C. Confined space
• D. None of these options are correct

Explanation: In chemistry, the term "surroundings" refers to everything outside of the system being studied.

• A. Initial conditions
• B. Final conditions
• C. Initial and final conditions
• D. Path of the reaction

Explanation: The change in volume of a system depends on either its pressure or temperature.

• A. Surrounding from the environment
• B. Reactants from contamination
• C. System from surrounding
• D. Products from surrounding

Explanation: The real or imaginary surface separating the 'system from the surrounding' is called the boundary.