All Free Chemistry MCQs with Answers

• A. I suggest that you, the seniors, he, and I form a team for the next competition.
• B. I suggest that the seniors you, he, and I form a team for the next competition.
• C. I suggest that you, I, he, the seniors, and form a team for the next competition.
• D. I suggest that I, the seniors, he, and you form a team for the next competition.

Explanation: Option D is correct. It uses the correct order of pronouns and places "I" first in the list, followed by "the seniors," "he," and "you."…

• A. Formic acid + acetic acid
• B. Two moles of methanoic acid
• C. Two moles of ethanoic acid
• D. Ethylene glycol

Explanation: 2-butene is a symmetrical alkene, and when it undergoes oxidative cleavage with hot alkaline KMnO4, each carbon-carbon double bond is…

• A. Multistep reaction
• B. Two step reaction
• C. Concerted reaction
• D. 3 step reaction

Explanation: SN1 (Substitution Nucleophilic Unimolecular) is a type of nucleophilic substitution reaction mechanism in organic chemistry, which…

• A. 2 step reactions
• B. Multistep reactions
• C. Single-step reactions
• D. None of these

Explanation: SN2 reactions are single-step reactions. This means that the bond breaking and bond forming steps happen at the same time.

• A. Iodine reacts slowly
• B. Iodine reacts reversibly
• C. The hydrogen iodide formed reduces the alkyl iodide to its starting material
• D. All of these options are correct

Explanation: Option A: Iodine is slightly soluble in water. It has the lowest standard reduction potential of the halogens, and is therefore the least…

• A. Multi-step reaction
• B. Two-step reaction
• C. Concerted reaction
• D. Three-step reaction

Explanation: The SN1 reaction is a nucleophilic substitution reaction where the rate-determining step is unimolecular.

• A. Solid
• B. Liquid
• C. Gas
• D. All of these

Explanation: SN1 reactions are favoured in polar protic solvent i.e.,the solvents that can form hydrogen bonds.This is because the large dipole moment…

• A. Alkenes
• B. Alkane
• C. Alkynes
• D. Alcohols

Explanation: Option B is correct as zinc carries out reductive dehalogenation of "alkyl halides" in which the halogen atom is replaced by a hydrogen…

• A. Transition state
• B. Intermediate
• C. Carbanion
• D. Carbene

Explanation: Option B is correct since SN1 reactions involve two steps and in the first step, carbonium ion form is positive.

• A. C-I
• B. C-H
• C. C-Cl
• D. C-F

Explanation: Fluorine has the highest bond energy because it has the smallest atomic radius and the highest electronegativity of all the halogens.

• A. Electrophilic carbon
• B. Nucleophilic carbon
• C. Beta-hydrogen
• D. None of these options is correct

Explanation: Chlorides generally give more elimination reactions than iodides, since the greater electronegativity of chlorine increases the acidity of…

• A. Substrate only
• B. Nucleophile
• C. Both A and B
• D. None of these

Explanation: Option C is correct since we know that an SN2 mechanism is a one-step process in which the nucleophile attacks the substrate and the…

• A. Electrophilic carbon
• B. Nucleophilic carbon
• C. Beta-hydrogen
• D. None of these

Explanation: This is the elimination reaction. In step 2 , which is the removal of β-hydrogen, base attacks β-hydrogen to form alkene.

• A. Nucleophilic unimolecular addition reactions
• B. Nucleophilic bimolecular substituition reactions
• C. Nucleophilic bimolecular addition reactions
• D. Nucleophilic unimolecular substitution reactions

Explanation: SN2 is a nucleophilic bimolecular substitution reaction. Hence, B is the correct option.

• A. Iodine reacts slowly
• B. Iodine reacts reversibly
• C. HI formed reduces alkyl iodide again to starting material
• D. All of these options are correct

Explanation: Alkyl iodides cannot be prepared directly by the halogenation of alkanes because iodine reacts slowly and reversibly as well as the…

• A. NH2ˉ
• B. H2O
• C. BF3
• D. CH3ˉ

Explanation: Nucleophiles are electron donors and they usually have a negative charge.

• A. R - Cl > R - Br > R - F > R - 1
• B. R -I > R - Br > R - CI > R - F
• C. R - I > R - CI > R - Br > R - F
• D. None of these

Explanation: The correct order of reactivity for alkyl halides in nucleophilic substitution reactions is generally R - I > R - Br > R - Cl > R - F…

• A. Deactivate the ring; meta directing
• B. Activate the ring; ortho-para directing
• C. Deactivate the ring; ortho-para directing
• D. Activate the ring; meta directing

Explanation: decreasesAmmonia is a meta-directing group. It is also a deactivating group.

• A. 1st order kinetics
• B. 2nd order kinetics
• C. Zero order kinetics
• D. None of these

Explanation: Option B is correct.Elimination bimolecular reactions involve second-order kinetics.

• A. They have an electrophilic carbon
• B. They have an electrophilic carbon and a good leaving group
• C. They have an electrophilic carbon and a bad leaving group
• D. They have a nucleophilic carbon and a good leaving group

Explanation: Option B is correct.Alkyl halides are considered to be very reactive compounds towards nucleophiles because they have an electrophilic…