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 646 of 686
- A. Atomic number
- B. Number of electrons
- C. Number of isotopes & their abundance
- D. None of the above
Explanation: Atomic mass depends on the number of isotopes and their abundance because:Isotopes of an element have the same atomic number but different…
Correct answer: Number of isotopes & their abundance- A. Soft drinks
- B. Bananas
- C. Milk of magnesia
- D. Sea water
Explanation: The basic pH of milk of magnesia helps neutralize overactive stomach acids that cause heartburn.
Correct answer: Milk of magnesia- A. 13
- B. 15
- C. 1.3
- D. 0.1
Explanation: A, B and D are incorrect because these are not correct percentage ionization valuesC is correct since The solution is given as CH3COOH…
Correct answer: 1.312904. The 'pH' of human blood is:
- A. 6.7 - 8
- B. 7.9
- C. 7.5
- D. 7.35 - 7.4
Explanation: The pH of human blood is typically around 7.35 to 7.45, which is slightly alkaline or basic.
Correct answer: 7.35 - 7.4- A. Ortho hydroxy benzene sulphonic acid
- B. Meta hydroxy benzene sulphonic acid
- C. Ortho and para hydroxy benzene sulphonic acid
- D. Para hydroxy benzene sulphonic acid
Explanation: Explanation:This product is formed in the reaction of phenol with concentrated sulfuric acid.
Correct answer: Ortho and para hydroxy benzene sulphonic acid- A. Br2/H2O
- B. FeSO4
- C. Cl2/H2O
- D. FeCl3
Explanation: Explanation:An aqueous solution of phenol reacts with bromine water to give white ppt of 2,4,6-tribromophenol .
Correct answer: Br2/H2O- A. 1.2 x 10^-10
- B. 1.2 x 10^10
- C. 1.3 x 10^10
- D. 1.3 x 10^-10
Explanation: A is incorrect.B is incorrect.C is incorrect.D is correct as disassociation constant of phenol is 1.3 x10-10 (fact)
Correct answer: 1.3 x 10^-10- A. Picric acid
- B. Nitro phenol
- C. Benzoic acid
- D. Malonic acid
Explanation: Picric acid is 2,4,6-trinitrophenol. Picric acid has a structure consisting of a phenolic ring with three nitro groups (-NO2) attached…
Correct answer: Picric acid- A. 2,4,6-tribromophenol
- B. 2-bromophenol
- C. 4-bromophenol
- D. Phenol
Explanation: Since the OH group has an electron donating effect, it is an ortho-para director. The following reaction occurs:
Correct answer: 2,4,6-tribromophenol- A. A
- B. B
- C. C
- D. D
Explanation: Carbons are numbered according to the placement of the -OH group. The carbon to which the OH group is attached is C1.
Correct answer: B- A. Phenol
- B. Ether
- C. Ethanol
- D. Methanol
Explanation: The antiseptic properties of phenol were used by Sir Joseph Lister (1827-1912).Phenol was one of the earliest disinfectants and…
Correct answer: Phenol- A. 1,3,6-Trinitrophenol
- B. m-Nitrophenol
- C. Tartaric acid
- D. Picric acid
Explanation: Picric acid, also called 2,4,6-trinitrophenol, is a pale yellow, odorless, crystalline solid that has been used as a military explosive…
Correct answer: Picric acid- A. The lone pair on the oxygen atom overlaps with the delocalized π- bonding system in benzene.
- B. Oxygen atom is directly bonded with the benzene ring in the phenoxide ion.
- C. The negative charge is localized on the oxygen atom of phenoxide ion.
- D. The negative charge is delocalized on oxygen atom of ethoxide ion.
Explanation: In phenoxide ion, the lone pair on the oxygen atom forms a delocalised pi system with the benzene ring by involving the electrons of the…
Correct answer: The lone pair on the oxygen atom overlaps with the delocalized π- bonding system in benzene.- A. Releases
- B. Does not radiate
- C. Absorbs
- D. None of these
Explanation: It's because there are only a limited number of stable states an electron in an atom can be in.
Correct answer: Does not radiate- A. Nitrogen
- B. Hydrogen
- C. Oxygen
- D. None of these
Explanation: In synthetic fibers, hydrogen bonding plays a crucial role in providing tensile strength.
Correct answer: Hydrogen- A. Acrylic resins
- B. Polyester resins
- C. PVCs
- D. Polyamide resins
Explanation: Polyester resins are synthetic resins formed by the reaction of dibasic organic acids and polyhydric alcohols.
Correct answer: Polyester resins- A. CH2=CH―CN
- B. CH3―CH2―CH2―CN
- C. CH3―CH2―CN
- D. CH3―CN
Explanation: Explanation:This is the formula of acrylonitrile, which is an organic compound used in the production of synthetic fibers and resins.
Correct answer: CH2=CH―CN12918. Macromolecules are described as large molecules built up from small repeating units known as:
- A. Monomers
- B. Isomers
- C. Metameres
- D. Tautomer
Explanation: A macromolecule is a very large molecule. That are composed of many covalently bonded atoms.
Correct answer: Monomers- A. Difluoroethane
- B. Chloroethane
- C. Chlorofluororyhane
- D. Tetrafluoroethane
Explanation: The non-stick lining of pans is made of Teflon/PTFE which is a polymer. Its monomer is tetrafluoroethane.
Correct answer: Tetrafluoroethane- A. -NH2-CO-
- B. -CO-O-
- C. -NH-CO-
- D. -NH-O-CO-
Explanation: Amide linkage is a covalent bond between COOH and NH2 of the amino acid. The linkage is CONH and a water molecule is eliminated.
Correct answer: -NH-CO-