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 624 of 686
12461. The first ionization potential of alkaline earth metal is greater than alkali metals because _.
- A. They are more reactive
- B. They have greater atomic radii
- C. They have smaller atomic sizes
- D. All of the above
Explanation: In general, as we move from left to right in a period, the ionization energy of the elements increases due to successive increase in the…
Correct answer: They have smaller atomic sizes12462. What is the general trend of melting and boiling points of transition elements along the period?
- A. Increases from left to right
- B. Decreases from left to right
- C. Increases up to the middle then decreases
- D. Decreases up to the middle and then increases
Explanation: The relationship between the melting and boiling points of transition elements within a period is directly influenced by the number of…
Correct answer: Increases up to the middle then decreases- A. 3A & 4A
- B. 5A & 6A
- C. 6A & 4A
- D. 3A and 6A
Explanation: The ionization energies of group IIIA and VIA show abnormal trends because elements of these groups tend to lose electrons easily to…
Correct answer: 3A and 6A- A. Neutral, excited
- B. Excited, de-excited
- C. De-excited, excited
- D. None of these options are correct
Explanation: When a light photon arrives at the metal surface, it is absorbed. This process promotes the electrons to a higher energy level.
Correct answer: Excited, de-excited- A. J/mol
- B. KJ/mol
- C. KJ/atom
- D. J/atom
Explanation: Electron affinity is defined as the change in energy "(KJ/mol)" of a neutral atom when an electron is added to the atom to form a negative…
Correct answer: KJ/mol- A. Removed,cation
- B. Added,cation
- C. Added, anion
- D. Removed, anion
Explanation: c) Added, anion: This is the correct option. Electron affinity is the energy released when an electron is added to an atom to form an…
Correct answer: Added, anion- A. 0.1, 0.2
- B. 0.1, 0.3
- C. 0.2, 0.4
- D. 0.2, 0.1
Explanation: 9.8 grams of sulphuric acid is 0.1 moles so there will be 0.2 moles of hydrogen ions ( two hydrogens per sulphuric acid molecule) H2SO4…
Correct answer: 0.2, 0.1- A. Picric acid
- B. Resorcinol
- C. Catechol
- D. P-Cresol
- E. Hydroquinone
Explanation: The explanation for this question will be added soon.
Correct answer: P-Cresol- A. Oxidation
- B. Reduction
- C. Dehydroxylation
- D. Dehydrogenation
Explanation: Benzene can be prepared from phenols too through their reduction. In this process, vapors of phenol are passed over heated zinc dust.
Correct answer: Reduction- A. Lucas test
- B. Halogenation
- C. Nitration
- D. Iodoform
Explanation: Phenols react with bromine water to give a white ppt. of 2,4,6-tribromophenol. Alcohols do not have any action with bromine water.
Correct answer: Halogenation- A. Reduction with hydrogen in the presence of Ni
- B. Reduction with zinc
- C. Reduction with alkali
- D. Reduction wilh acids
Explanation: Phenols, on heating with Zn dust yield aromatic hydrocarbons.
Correct answer: Reduction with zinc- A. Colorless crystalline solid
- B. White crystalline deliquescent solid
- C. Colorless amorphous solid
- D. Colorless amorphous deliquescent solid
Explanation: Pure phenol is a white crystalline solid, smelling of disinfectant.
Correct answer: White crystalline deliquescent solid- A. Lucas test
- B. Halogenations
- C. Nitration
- D. Idoform test
Explanation: phenol forms white precipitates when reacted with Bromine while alcohol does notP
Correct answer: Halogenations12474. Phenol is known as:
- A. Carpolic acid
- B. Carbonylic acid
- C. Carbolic acid
- D. Carbolylic acid
Explanation: The other name for phenol is Carbolic acid.
Correct answer: Carbolic acid- A. Delocalization of negative charge in OH group
- B. Delocation of positive charge on the carbon atom in ring
- C. Delocalization of negative charge in the ring
- D. Delocalization of positive charge in the OH group
Explanation: Phenol is more acidic than alcohols due to stabilisation of phenoxide ion through resonance of negative charge in the ring.
Correct answer: Delocalization of negative charge in the ring- A. Salicylic acid
- B. Picric acid
- C. Cresol
- D. O-nitrophenol
Explanation: Option A: Salicylic acid is a phenol derivative with a hydroxyl group (-OH) attached to an aromatic ring.
Correct answer: Picric acid12477. Which of the following major product(s) is formed when phenol reacts with sulphuric acid at 100 °C?
- A. Ortho-hydroxy benzene sulphonic acid
- B. Para-hydroxy benzene sulphonic acid
- C. Meta-hydroxybenzene sulphonic acid
- D. Both a and b
Explanation: The reaction of phenol with concentrated sulphuric acid is thermodynamically controlled.
Correct answer: Para-hydroxy benzene sulphonic acid- A. OH group
- B. Phenoxide ion
- C. Benzene ring
- D. All of these options are correct
Explanation: OPTION A: Phenol is an aromatic alcohol, and the presence of a hydroxyl (OH) group in the molecule makes it an electrophilic substrate.
Correct answer: OH group- A. Due to presence of resonance in phenol
- B. Due to the absence of resonance in alcohol
- C. Both Options A and B are correct
- D. Because in phenol, hydrogen is attached to oxygen
Explanation: The answer is Both Options A and B are correct. Phenol is more acidic than alcohol because of two reasons: The presence of resonance in…
Correct answer: Both Options A and B are correct- A. Alcohol
- B. Carboxylic acids
- C. Esters
- D. Amines
Explanation: Acetyl chloride, CH3COCl , which is a derivative of carboxylic acid but more reactive, will react with phenol in the presence of NaOH to…
Correct answer: Esters