All Free Chemistry MCQs with Answers

• A. 0.05
• B. 0.25
• C. 0.35
• D. 0.45

Explanation: Partial pressure = moles of substance/total moles * total pressure =moles of N2/total moles * total pressure =1/4 * 1 atm = 0.25

• A. dimension (i.e., with no unit)
• B. mole dm3
• C. mole dm-3
• D. mole2 dm3

Explanation: The correct unit for the reaction N2O4 g → 2NO2 g is mole dm-3, as it represents the concentration of the substances involved in the…

• A. Glass vessel
• B. Iron vessel
• C. Open vessel
• D. Closed vessel

Explanation: At equilibrium, the rate of forward reaction equals the rate of reverse reaction.

• A. When forward and backward reaction taking place at the same rate
• B. Reaction takes place
• C. The forward and backward
• D. There are two reactions with one faster than the other

Explanation: At equilibrium, the rates of the forward and backward reactions are equal, and there is no net change in the concentrations of the…

• A. Is the same at different temperature?
• B. Is different at different temperature
• C. Is negligible at room temperature
• D. Can be same at different temperatures

Explanation: The value of K (equilibrium constant) for a reaction can be different at different temperatures.

• A. Kc is very large
• B. Kc is very small
• C. Kc is neither very small nor very large
• D. Kc is equal to 1

Explanation: The reaction given is:2Cl(g) \rightleftharpoons Cl_2(g)The equilibrium constant, K_c, is defined as the ratio of the concentrations of the…

• A. Kc = [Ce3+][Fe3+]/[Ce4+][Fe2+]
• B. Kc = [Ce3+][Fe2+]/[Ce4+][Fe3+]
• C. Kc = [Ce4+][Fe3+]/[Ce3+][Fe2+]
• D. Kc = [Ce3+][Fe2+][Ce4+][Fe3+]

Explanation: The correct equilibrium constant expression, Kc, for the given reaction is Kc = [Ce3+][Fe3+]/[Ce4+][Fe2+].

• A. Raoult's Law
• B. Le Chatelier's Principle
• C. The law of conservation of energy
• D. The law of mass action

Explanation: The correct answer is the law of mass action. This law specifically states that the rate of a chemical reaction is proportional to the…

• A. Kp = Kc
• B. Kp < Kc
• C. Kp > Kc
• D. Kp < 0

Explanation: Kp and Kc are equilibrium constants for reactions involving gases. Kp is used when partial pressures are involved, while Kc is used for…

• A. Conversion of A to B is 50% complete
• B. 50% reactant has been changed to B
• C. Rate of transformation of A to B is equal to B to A
• D. Complete conversion of A to B has taken place

Explanation: When a chemical reaction is in equilibrium, it means that the rate at which A transforms into B is equal to the rate at which B transforms…

• A. High yield
• B. No yield
• C. Moderate yield
• D. Low yield

Explanation: When the value of K, which represents the equilibrium constant, is very small, it indicates that the reaction has a low yield.

• A. H2NCONH2
• B. NH4COONH4
• C. H2NCOONH2
• D. NH2COONH4

Explanation: Ammonium carbamate is a salt formed by the reaction of ammonia with carbon dioxide or carbamic acid.

• A. Water brings them close
• B. Water helps them in bonding
• C. Water dissolve them in ions
• D. Water reacts with them

Explanation: When substances dissolve in water, they often undergo a process called hydration, where the water molecules surround and separate the…

• A. [Ag(NH3)2]Cl
• B. [Ag(NH3)]Cl
• C. [Ag(NH3)4]Cl
• D. [Ag(NH3)6]Cl

Explanation: When ammonium hydroxide is added to silver chloride, the silver chloride dissolves in the ammonia to form a diamine complex: [Ag(NH3)2]Cl.

• A. NH4Cl
• B. NaNO3
• C. Na2CO3
• D. Na2SO4

Explanation: The correct answer is Na2CO3. Sodium carbonate forms an alkaline solution because it undergoes hydrolysis in water, releasing hydroxide…

• A. H2BO2
• B. (C2H5)3BO3
• C. Ca2B6O115H2O
• D. Na2B4O710H2O

Explanation: Per one molecule of borax, there are 10 molecules of water of crystallization. Hence, metaborate is formed in the borax bead test.

• A. Ca(OH)2
• B. SiCl4
• C. KCl
• D. SrCl2

Explanation: KCl is a strong electrolyte because it fully dissociates into ions (K+ and Cl-) in water, allowing efficient conduction of electricity.

• A. 4
• B. 6
• C. 8
• D. 2

Explanation: The coordination number of an ion refers to the number of ions or atoms that surround and are bonded to the central ion in a compound.

• A. Covalent
• B. Electrovalent
• C. Hydrogen bond
• D. Coordinate covalent bond

Explanation: Coordinate covalent bond: A coordinate covalent bond is formed when one atom donates a pair of electrons to be shared with another atom.

• A. Ionic
• B. Covalent
• C. Coordinate covalent
• D. None of the above

Explanation: Covalent bonds involve the sharing of electrons between atoms. Boron typically forms covalent bonds by sharing electrons with hydrogen.