All Free Chemistry MCQs with Answers

• A. Be²⁺ < Mg²⁺ < Ca²⁺ < Sr²⁺ < Ba²⁺
• B. Ba²⁺ < Sr²⁺ < Ca²⁺ < Mg²⁺ < Be²⁺
• C. Sr²⁺ < Ba²⁺ < Ca²⁺ < Mg²⁺ < Be²⁺
• D. Ba²⁺ < Sr²⁺ < Mg²⁺ < Ca²⁺ < Be²⁺

Explanation: Hydration energy is the energy released when ions are hydrated. It is directly proportional to the charge density (charge/radius ratio) of…

• A. Ionization energy
• B. Solubility of their hydroxides
• C. Solubility of their sulphate
• D. Electronegativity

Explanation: As you move down Group 2, the solubility of the hydroxides, M(OH)₂, generally increases.

• A. Na2CO3
• B. CaCO3
• C. Ca(HCO3)2
• D. NaHCO3

Explanation: The reactions are CaCO₃(s) → CaO(s) + CO₂(g) (X → residue + gas); CaO(s) + H₂O → Ca(OH)₂(aq) (Y); Ca(OH)₂(aq) + CO₂ → CaCO₃(s) (Z, which…

• A. H2
• B. Na
• C. CO2
• D. O2

Explanation: Brine is a highly concentrated solution of NaCl. Cathode is where reduction takes place and oxidation takes place on anode.

• A. Hydroxide ions to reach the anode
• B. Chlorine gas to mix
• C. Cathode to decay
• D. All of the above

Explanation: Option A is correct as that makes sure that the flow of liquid is always from "left to right" - preventing any of the sodium hydroxide…

• A. B & Al
• B. Ca & Mg
• C. Si & Al
• D. All

Explanation: The nine most common elements in the Earth's crust are roughly 46% oxygen, 28% silicon, 8.3% aluminium, 6.9% iron, 2.4% calcium, 2.5%…

• A. Size of atoms
• B. Nuclear Charge
• C. Number of shells
• D. All of these options are correct

Explanation: Option D is correct since all of the options mention the correct reasons for the ionization energy trend and all three reasons have to be…

• A. Sodium sulfate
• B. Potassium sulfate
• C. Zinc sulfate
• D. Barium sulphate

Explanation: Option D is correct since barium sulfate is an insoluble white solid with a low solubility product.

• A. Simple ions.
• B. Strong anions.
• C. Double salts.
• D. Complex ions.

Explanation: When a compound of a transition element is dissolved in a solution of salt, it will form complex ions.

• A. Ionisation state
• B. Oxidation state
• C. Electronic configuration
• D. Formation of complexes

Explanation: Both lanthanides and actinides have similar electronic configurations. They both have their valence electrons in f-orbitals, which are…

• A. Being s-block elements
• B. Inert gas configurations
• C. Ns1 electronic configuration
• D. Being metals

Explanation: Second ionization energy can be defined as the removal of one mole of electron from the one mole of monovalent gaseous cation of the…

• A. They are more reactive.
• B. They have greater atomic radii.
• C. They have smaller atomic sizes.
• D. All

Explanation: Correct option is C. Alkaline earth metals have smaller atomic sizes as compared to alkali metals so electrons of outermost shells of…

• A. HCO3-
• B. NaOH
• C. KOH
• D. CsOH

Explanation: lonic character, melting point, boiling point, reactivity, thermal stability and solubility in water increase from Li to Cs due to…

• A. Solid form
• B. Molten form
• C. Aqueous form
• D. Both Options B and C are correct

Explanation: Ionic salts of alkali metals can conduct electricity when they are in the aqueous or molten form.

• A. A
• B. B
• C. C
• D. D

Explanation: When heated, alkaline earth metal hydroxides undergo thermal decomposition to produce the corresponding metal oxide and water.

• A. The oxide layer exposes the metal to Atmospheric attack
• B. The oxide layer increases the reactivity of metal
• C. The oxide layer protects the metal from further atmospheric attack
• D. The oxide layer gives the metal a shiny silvery appearance

Explanation: The oxide layer can not react with air, and makes a physical barrier between air and metal.

• A. Lubricant
• B. Solvent
• C. Oxidant
• D. Plastic

Explanation: Carbon tetrachloride (CCl4) is used as a solvent in industries.

• A. MgO
• B. CaO
• C. BaO
• D. SrO

Explanation: Solubility of alkaline earth metal oxides in water increases as we move from top to bottom because lattice energy decreases faster than…

• A. Amphoteric
• B. Neutral
• C. Acidic
• D. Basic

Explanation: The nature of an aqueous solution of ammonia (NH3) is basic. This is because ammonia can accept a proton from water, forming ammonium…

• A. Atoms of II-A elements have smaller size
• B. II-A elements are more reactive
• C. Atoms of II-A elements provide two binding electrons
• D. I-A elements have smaller atomic radius

Explanation: Metallic character as well as melting and boiling increase until period number three because the number of free electrons available for…