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 636 of 686
12701. Ethylene glycols are used as
- A. Anesthetic
- B. Knocking agent
- C. Freezing agent
- D. Anti-freezing agent
Explanation: Ethylene glycol is used as an antifreeze agent and polyester.
Correct answer: Anti-freezing agent- A. Lucas test
- B. Iodoform test
- C. Baeyer's test
- D. Silver mirror test
Explanation: The Lucas test differentiates between primary, secondary, and tertiary alcohols.
Correct answer: Lucas test- A. Amino group
- B. Hydroxyl group
- C. Halide group
- D. Hydride group
Explanation: When a -OH group(hydroxyl group) containing organic compound is reacted with with phosphorus pentachloride, it forms HCI an halogen by the…
Correct answer: Hydroxyl group- A. Methanol
- B. Lactic acid
- C. Pyridine
- D. Acetone
Explanation: Methanol, pyridine and acetone are able to denature ethanol.Denaturation refers to the process of rendering alcohol undrinkable or…
Correct answer: Lactic acid- A. By Lucas test
- B. By silver mirror test
- C. By oxidation
- D. By Iodoform test
Explanation: The solution in the ethanol test tube should go cloudy and then a yellow precipitate of tri-iodomethane (iodoform) should be seen.
Correct answer: By Iodoform test- A. Calcium oxide
- B. Calcium chloride
- C. Calcium carbonate
- D. Carbon monoxide
Explanation: if we add lime (CaO) to the rectified spirit then the water of the mixture can be absorbed by the lime.
Correct answer: Calcium oxide- A. Primary
- B. Secondary
- C. Tertiary
- D. Polyhydride
Explanation: It is a tertiary alcohol. We can recognize the tertiary alcohol by seeing whether the C atom attached to the OH group (also known as alpha…
Correct answer: Tertiary- A. Less acidic than water
- B. Less basic than phenol
- C. More acidic than phenol
- D. More acidic than water
Explanation: The concentration of H+ ions determines the acidity. More H+ ions means the solution is more acidic as in the case of water while alcohol…
Correct answer: Less acidic than water- A. Oxidative cleavage
- B. Thermal cracking
- C. Catalytic cracking
- D. Steam cracking
Explanation: A is incorrect as oxidative cleavage does not produce gasoline with a high octane number.A reaction in which a carbon-carbon bond is…
Correct answer: Catalytic cracking- A. Sabatier Sender's Reaction
- B. Hydrogenolysis Reaction
- C. Reduction Reaction
- D. Kolbe's Electrolytic Reaction
Explanation: A is incorrect as Sabatier-Sender's reaction is the reaction in which preparation of ethane is done by the catalytic hydrogenation of…
Correct answer: Kolbe's Electrolytic Reaction- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: There are methyl groups (CH3) on carbons 2, 3 and 4 in option A only.
Correct answer: Option A- A. C2H4 + 3O2 → 2CO2 + 2H2O
- B. CH4 + 2O2 → CO2 + 2H2O
- C. CH4 + 12 O2 = CH3OH (conditions: (Conditions:Cu, 400°C, 200 atm)
- D. C2H2 + 5/2 O2 → 2CO2 + H2O
Explanation: Key points here: The products of combustion are always H2O and C02 2-saturated means those having in which carbon form only single bonds
Correct answer: CH4 + 2O2 → CO2 + 2H2O- A. Mixture of SiO2 and Ni
- B. Mixture of Pt and Cu
- C. Mixture of Fe and MgO
- D. Mixture of SiO2 and Al2O3
Explanation: The catalysts required in catalytic cracking are usually solid acidic catalysts that are a mixture of SiO2 and Al2O3
Correct answer: Mixture of SiO2 and Al2O3- A. Finely divided nickel
- B. Finely divided iron
- C. Vanadium pentaoxide
- D. Copper
Explanation: The hydrogenation of unsaturated oils is done under high temperature and pressure with nickel used as a catalyst.
Correct answer: Finely divided nickel- A. 3, 3-dimethyl-3-hexene
- B. 3, 4-dimethyl-3-hexene
- C. 3-hexene
- D. 2,3-dimethyl-1-hexene
Explanation: KEY POINTS the structure is a six-carbon Hydrocarbon containing two methyl substitutions and a double bond Metal substitution are present…
Correct answer: 3, 4-dimethyl-3-hexene- A. Reduction
- B. Oxidation
- C. Hydroxylation
- D. Hydration
Explanation: In a hydration reaction, a water molecule is added to the unsaturated reactants to form an alcohol.
Correct answer: Hydration- A. Detection of ketones
- B. Detection of double bond
- C. Identification of Primary and Secondary alcohols
- D. Detection of Aldehydes
Explanation: The electrophilic addition of bromine to Alkenes in the cold with pure liquid bromine, or with a solution of bromine in an organic solvent…
Correct answer: Detection of double bond12718. Alkenes undergo:
- A. Electrophilic Addition
- B. Electrophilic substitution
- C. Nucleophilic substitution
- D. Nucleophilic addition
Explanation: Alkenes have a pi bond between carbon atoms, which is an area of electron density i.e.
Correct answer: Electrophilic Addition- A. Nitrogen dioxide
- B. Dinitrogen trioxide
- C. Nitrous oxide
- D. Nitric oxide
Explanation: Explanation:The yellowish color of photochemical smog is primarily due to the presence of nitrogen dioxide (NO2), which is a…
Correct answer: Nitrogen dioxide- A. One half
- B. Not affected
- C. One third
- D. Two third
Explanation: Explanation:The incarnation process can reduce the volume of the water by two third. These options are also incorrect.
Correct answer: Two third