All Free Chemistry MCQs with Answers

• A. Increases on dilution slightly
• B. Does not change on dilution
• C. Decreases on dilution
• D. Depends on density of electrolyte itself

Explanation: When a strong electrolyte (a compound that completely dissociates into ions in solution) is diluted, the number of ions per unit volume…

• A. It lies above in electrochemical series
• B. It lies below in the electrochemical series
• C. Cannot replace
• D. None

Explanation: The electrochemical series is a list of metals arranged in order of their standard electrode potentials.

• A. Presence of unpaired electron in atom and molecule
• B. Weakly attracted by strong magnetic field
• C. Weakly repelled by strong magnetic field
• D. Both A and B are correct

Explanation: Overall, option D (Both A and B are correct) accurately describes the true statements about the paramagnetic property of transition…

• A. More carbon content in cutting tools
• B. More iron content in cutting tools
• C. More sulphur and phosphorous content in cutting tools
• D. None of the above options

Explanation: Tubes made of steel can be hammered while hot because they typically have a lower carbon content compared to cutting tools made of steel.

• A. Electrons are tightly held by sigma bond in alkanes, thus less reactive
• B. Electrons cloud away from nuclei due to pi bond in alkenes, thus more reactive
• C. Pi bonds make alkenes reactive to electrophilic reagents
• D. All of the above

Explanation: Alkanes are less reactive compared to alkenes primarily because of the nature of the bonds present in their molecular structure.

• A. They decompose when heated
• B. Become hard on heating and cannot be softened again
• C. Can be softened on heating and hardened when cooled with drastically different properties fromoriginal
• D. Can be softened repeatedly on heating and hardened when cooled with little change in property

Explanation: Polymers used in PVC pipes exhibit the property of thermoplasticity, which means they can be softened upon heating and hardened upon…

• A. d-d transition
• B. d-p transition
• C. p-p transition
• D. s-d transition

Explanation: Transition elements are characterized by having partially filled d-orbitals in their atoms or ions.Color in transition metal compounds…

• A. Crystalline structure
• B. Characteristic color
• C. Hardness
• D. Higher reactivity

Explanation: As we discussed earlier, the color of transition metal compounds is directly related to d-d transitions.When light interacts with a…

• A. Ionic
• B. Covalent
• C. Both a and b
• D. None of these

Explanation: Ionic compounds: Transition metals often form ionic compounds where the metal ion is surrounded by ligands (non-metal ions or molecules).

• A. Titanium
• B. Chromium
• C. Manganese
• D. Vanadium

Explanation: Boiling point is generally related to the strength of metallic bonding.

• A. V
• B. Nb
• C. Ta
• D. La

Explanation: Lanthanum (La) is a lanthanide element, not a transition metal. It belongs to the 3rd transition series and has its d-orbitals completely…

• A. Blue crystalline solid
• B. Not soluble in water
• C. Strong oxidizing agent
• D. Used in formation of lead chromate

Explanation: Potassium dichromate (K₂Cr₂O₇) is a bright orange crystalline solid, not blue.It is a strong oxidizing agent, meaning it readily accepts…

• A. Ceramic acid
• B. Chromic Acid
• C. Dichromate
• D. None of these

Explanation: When potassium dichromate (K₂Cr₂O₇) is acidified, it forms chromic acid (H₂CrO₄).

• A. They can make colored complexes
• B. They can be used as a catalyst
• C. They have only one valency
• D. They are d block elements

Explanation: Transition metals are known for their variable valencies. This means they can form ions with different charges due to the involvement of…

• A. 2
• B. 3
• C. 5
• D. 4

Explanation: Ferrous ion (Fe²⁺) has the electronic configuration [Ar] 3d⁶.To determine the number of unpaired electrons, we need to fill the d-orbitals…

• A. Zn
• B. Fe
• C. Co
• D. Mn

Explanation: As we discussed earlier, magnetic properties are related to the presence of unpaired electrons.Zinc (Zn) has a completely filled…

• A. Cu⁺
• B. Cu²⁺

Explanation: The cupric ion (Cu²⁺) is more stable than the cuprous ion (Cu⁺). This is because the Cu²⁺ ion has a completely filled d¹⁰ configuration…

• A. [MnCl₄]²⁻
• B. PCl₅
• C. [Cu(NH₃)₄]²⁺
• D. [Co(NH₃)₆]³⁺

Explanation: Square planar geometry is most commonly observed in complexes with a d⁸ electronic configuration.[Cu(NH₃)₄]²⁺ has a copper(II) ion (Cu²⁺)…

• A. f block
• B. s block
• C. d block
• D. p block

Explanation: Lanthanide Contraction is a phenomenon observed in the lanthanide series (f-block elements).

• A. [MnCl4]-2
• B. [Cu(NH3)4]+2
• C. [Fe(CN)6]-4
• D. [PtF6]-2

Explanation: Because it exists as square planar and has 4 ligands attached to the central atom.