All Free Chemistry MCQs with Answers
Every Chemistry question in the bank, across all chapters, each with the correct answer and a written explanation. Free and unlimited, with no account needed.
13,720 questions · page 672 of 686
- A. NH3
- B. OH
- C. CN-
- D. Br2
Explanation: Br₂ is not a nucleophile because:No Significant Negative Charge:Nucleophiles are electron-rich species that donate electrons.Br₂ is a…
Correct answer: Br2- A. Secondary amine
- B. Tertiary amine
- C. Quaternary ammonium salt
- D. Mixture of (a), (b) & (c)
Explanation: When primary amines are treated with alkyl halides, they undergo a series of nucleophilic substitution reactions.
Correct answer: Mixture of (a), (b) & (c)- A. C6 H5O
- B. H-O-
- C. NH3
- D. C2 H5 O-
Explanation: Nucleophilicity increases as the density of negative charge increases. An anion is always a better nucleophile than a neutral molecule, so…
Correct answer: H-O-- A. Electrophile
- B. Nucleophile
- C. Lewis base
- D. None
Explanation: An electron-deficient species is one that has a deficiency of electrons, making it "electron-seeking" or electron-loving.
Correct answer: Electrophile- A. Inversion only
- B. Retention only
- C. Equal inversion and retention
- D. More inversion and retention
Explanation: In SN1 reactions, the formation of a planar carbocation allows for nucleophilic attack from either side, resulting in both inversion and…
Correct answer: More inversion and retention- A. H2O
- B. AlCl3
- C. BF3
- D. Cl2
Explanation: A nucleophile is a species that donates a pair of electrons to form a covalent bond with an electrophile.
Correct answer: H2O- A. Bimolecular
- B. Unimolecular
- C. Trimolecular
- D. Tetramolecular
Explanation: The molecularity of a reaction is defined as the number of reacting molecules that collide simultaneously to bring about a chemical…
Correct answer: Bimolecular- A. Oxidation of Ag
- B. Reduction of Cu
- C. Oxidation of Cu
- D. Ionization of Ag
Explanation: When copper wire is placed in silver nitrate solution then the solution becomes blue colored.
Correct answer: Oxidation of Cu13429. Silver nitrate solution turns blue when a piece of copper is added to it. This is because of:
- A. Oxidation of Ag
- B. Reduction of Cu
- C. Oxidation of Cu
- D. Reduction of Ag
Explanation: When copper is added to silver nitrate solution, the following reaction takes place:
Correct answer: Oxidation of Cu- A. -6
- B. +6
- C. -4
- D. +4
Explanation: In sulfuric acid (H2SO4), Hydrogen exists in its normal oxidation state of +1 and Oxygen exists in its normal oxidation state of -2.
Correct answer: +6- A. Ag
- B. Au
- C. Al
- D. Zn
Explanation: In a displacement reaction, a more reactive metal can displace a less reactive metal from its salt solution.
Correct answer: Zn- A. -1
- B. +3
- C. +5
- D. -6
Explanation: This has to be calculatedThe oxidation state of Ca is +2, and oxygen is -2, so:(+2) + (2x) + (6 x -2) = 0; calculating this gives x = +5
Correct answer: +5- A. Ag
- B. AU
- C. Pt
- D. Zn
Explanation: A more reactive metal can displace a less reactive metal from its salt in an aqueous solution.
Correct answer: Zn- A. -1
- B. +3
- C. +5
- D. -6
Explanation: In the compound Ca(ClO3)2, calcium has an oxidation state of +2, being a Group 2 metal. Each ClO3- ion must balance to -1 overall charge.
Correct answer: +5- A. +3
- B. +2
- C. +4
- D. +6
Explanation: OPTION B is correct as there six ligands in the compound which is a cyano group having a charge of -1.
Correct answer: +2- A. Oxidize the compound
- B. Reduce the compound
- C. Electrolyze the compound
- D. None of the above
Explanation: Oxidize the compound: A stronger reduction potential indicates that the compound is more likely to undergo reduction rather than…
Correct answer: Oxidize the compound- A. MnO2
- B. Cl2
- C. NaOH
- D. Na2O2
Explanation: NaOH is not an oxidizing agent. It is a strong base that does not readily accept electrons or participate in redox reactions.
Correct answer: NaOH- A. Cl^-
- B. Ne
- C. Na
- D. Ca
Explanation: The correct answer is Ca. Calcium, as a metal, has a low electronegativity and readily donates electrons, making it a strong reducing…
Correct answer: Ca- A. Small negative values
- B. Large negative values
- C. Small positive values
- D. Large positive values
Explanation: The correct answer is Large negative values. A strong reducing agent has a large negative standard reduction potential.
Correct answer: Large negative values- A. I-1> Br->Cl-> F-
- B. F->Cl-> Br-> l-
- C. l-1>Cl-> F-> Br-
- D. Br->Cl-> l-> F-
Explanation: From the reduction potential values, it can be seen that iodide is the best-reducing agent.
Correct answer: I-1> Br->Cl-> F-