All Free Chemistry MCQs with Answers

• A. α-helix
• B. Both A and C
• C. β-sheets
• D. 3-dimensional folding

Explanation: The secondary structure refers to the local, regular folding patterns of the polypeptide chain.

• A. Hydrogen bonding
• B. Covalent bonding
• C. Debye forces
• D. Dipole-Dipole forces

Explanation: The primary structure, which is the sequence of amino acids. is held together by strong peptide bonds.

• A. H-Bonds
• B. Disulphide linkages
• C. Covalent bonds
• D. Amino acids

Explanation: Disulfide linkages (or bridges) are covalent bonds formed between the side chains of two cysteine residues.

• A. Animals
• B. Plants
• C. Human beings
• D. Both A and C

Explanation: Globulin proteins are primarily found in animals, including humans, where they perform critical roles in the blood plasma.

• A. Calopresti has made only three films so far, yet who is already a major force in Italian cinema.
• B. Calopresti has made only three films so far, yet him is already a major force in Italian cinema.
• C. Calopresti has made only three films so far, yet whom is already a major force in Italian cinema.
• D. Calopresti has made only three films so far, yet he is already a major force in Italian cinema.

Explanation: This option is correct. "He" is the subject pronoun that correctly refers to Calopresti, who is already established as a major force in…

• A. BH3
• B. NH3
• C. -NH2
• D. -OH

Explanation: A nucleophile is a chemical species that donates a lone pair of electrons to form a chemical bond to another electron deficient species.

• A. Hydrogen resembles in properties with IA, IVA and VIIA elements
• B. Hydrogen resembles in properties with IIIA, IVA and VA elements
• C. Hydrogen resembles in properties with IIA, IVA and VIA elements
• D. Hydrogen resembles in properties with IIA, IIIA and VIIA elements

Explanation: Hydrogen's placement at the top of Group IA is due to its similarity in properties with alkali metals, such as having one electron in its…

• A. Group IA
• B. (b) Group IB.
• C. Group VIIA:
• D. Group VIII

Explanation: - **Correct Option: (b) Group IB** Explanation: Group IB elements typically have lower ionization energies and electron affinities…

• A. All the metals are good conductors of electricity
• B. Non-metals have high ionization energies
• C. Alkali metals have low melting points
• D. Halogens are highly reactive non-metals

Explanation: Some metals, like Bismuth and Mercury, are poor conductors of electricity.

• A. Dobereiner
• B. Mendeleev
• C. Newlands
• D. Meyer

Explanation: Dobereiner observed that when elements are arranged in order of increasing atomic weight, every third element shows similar properties.

• A. Aluminum
• B. Silicon
• C. Zinc
• D. Germanium

Explanation: Mendeleev predicted the existence of several elements based on gaps in his periodic table.

• A. Less reactive
• B. Zero group elements
• C. Completely filled valence shell
• D. All of the above

Explanation: Noble gases are named for their inert nature, characterized by three significant features:Less reactive: Due to their completely filled…

• A. Boron & Beryllium
• B. Nitrogen & Phosphorous
• C. Magnesium & Aluminium

Explanation: Elements within the same group (vertical column) in the periodic table share similar chemical properties due to having the same number of…

• A. Alkali metals
• B. Alkaline earth metals
• C. Elements from Li to Ne
• D. Halogens

Explanation: As we move across a period (horizontal row) in the periodic table from left to right, the atomic number increases,meaning more protons and…

• A. Location of nucleus by Rutherford
• B. Atomic number by Moseley
• C. X-rays by Roentgen
• D. Natural radioactivity by Henry Becquerel

Explanation: While Mendeleev successfully organized elements based on their atomic mass, some anomalies and inconsistencies existed in his periodic…

• A. H+
• B. Atomic radii
• C. Cl-
• D. All are stable

Explanation: Correct: The chloride ion (Cl-) is stable in aqueous solution because it has achieved a stable octet configuration (eight electrons in its…

• A. Nuclear charge only
• B. Atomic size only
• C. Shielding effect only
• D. All of the above and nature of orbital

Explanation: Correct: Ionization energy, the energy required to remove an electron from an atom, is influenced by multiple factors:Nuclear charge…

• A. Increase
• B. Decrease
• C. Remain constant
• D. Remain same

Explanation: As we move down a group in the VII-A group (halogens), the atomic size increases due to additional electron shells.

• A. Mg > Sr
• B. Ba > Mg
• C. Lu > Ce
• D. Cl > I

Explanation: Within the same group (column) in the periodic table, atomic size increases as we move down.

• A. Magnesium and Lead
• B. Magnesium and Aluminium
• C. Aluminium and Zinc
• D. Aluminium and Mercury

Explanation: Magnalium is an alloy of aluminium with magnesium and small amounts of nickel and tin.