All Free Chemistry MCQs with Answers

• A. Iron
• B. Nickel
• C. Cobalt
• D. Barium

Explanation: Barium is not a ferromagnetic material. Ferromagnetic materials have a strong magnetic response to an external magnetic field, and they…

• A. [Cr (H2 O)5Cl] Cl3
• B. [Cr (H2 O)5Cl] Cl2
• C. [Cr (H2 O)5 Cl2] Cl
• D. [Cr (H2 O)5 Cl3] Cl

Explanation: 'Chloro' in the name suggests the presence of one chlorine in the ligand complex, Penta (5) aqua (H2O) shows that there are five water…

• A. Cr2+, Co2+, Cu2+
• B. Cu2+, Zn2+, Ti4+
• C. Ti3+, Zn2+, Cu2+
• D. Cr3+, Ti4+, Cu2+

Explanation: The correct answer is Option A: Cr2+, Co2+, Cu2+. These transition metal ions possess unpaired d-electrons, allowing for d-d electronic…

• A. [Cu(H2O)2 (NH3)2 (OH)2]
• B. [Cu(NH3)4 (OH)2]
• C. [Cu (NH3)4 (H2O)2]2+
• D. [Cu (NH3)3 (H2O)3]2+

Explanation: Ammonia acts as a ligand in this reaction, replacing water molecules in the coordination sphere of the copper ion, forming…

• A. [Co(en)2Cl2]
• B. [Co(en)2Cl2]2-
• C. [Co(ebn)2Cl2]1-
• D. [Co(en)2Cl2]1+

Explanation: The correct formula for Dichloro-Bis-ethylenediamine cobalt (II) is [Co(en)2Cl2].

• A. Blue
• B. Greenish blue
• C. Bluish green
• D. Colourless

Explanation: Transition elements exhibit color due to d-d transition. d-d transition is possible only when the d subshell has unpaired electrons.

• A. Cr
• B. Mn
• C. Zn
• D. Fe

Explanation: Zinc (Zn) is considered a non-typical transition element because it does not exhibit typical transition metal properties like variable…

• A. 3d
• B. 4d
• C. 5d
• D. 6d

Explanation: In the fourth transition series, the subshell that is in the process of completion is the 3d subshell.

• A. Fe
• B. Co
• C. Sb
• D. Ni

Explanation: Antimony (Sb) is not ferromagnetic. It is considered a diamagnetic material, which means it is weakly repelled by both poles of a magnet…

• A. Alcoholic KOH
• B. Aqueous KOH
• C. Aqueous NaOH
• D. Alcoholic HaOH

Explanation: The suitable reagent used for dehydrohalogenation of alkyl halides would be alcoholic KOH. Here are some examples.

• A. 2-Methyl propane
• B. 2-Methyl propene
• C. 2-Methyl-1 propanol
• D. 2-pentanol

Explanation: The unimolecular elimination (E1) reaction of 2-Bromo-2-methyl propane involves the removal of the bromine atom, resulting in the…

• A. Nucleophilic substitution reaction
• B. Elimination reaction
• C. Nucleophilic addition
• D. None of the above

Explanation: It should be noted that whenever the reagent is alcoholic / ethanolic KOH or NaOH, the reaction that follows is elimination

• A. Zn dust
• B. Conc. H2SO4
• C. Alcoholic KOH
• D. Aqueous KOH.

Explanation: Dehydrohalogenation of an alkyl halide is carried out in the presence of alcoholic KOH (potassium hydroxide dissolved in alcohol).

• A. Substrate reaction
• B. Elimination reaction
• C. Oxidation reaction
• D. Free radical reaction

Explanation: A greater number of alkyl groups on a substrate favors elimination reactions because it leads to the formation of more stable and…

• A. Constant Volume
• B. Constant Pressure and volume
• C. Variable pressure
• D. Constant pressure

Explanation: Enthalpy is a thermodynamic state function that represents the internal energy of a system plus the product of pressure and volume.

• A. 0.1
• B. 1.0
• C. 29.8
• D. Zero

Explanation: The correct answer is Zero. In thermodynamics, the standard enthalpy of formation for an element in its most stable form at 1 atm pressure…

• A. △H = q + P△V
• B. △H = △E- P△V
• C. △H = △E + P△V
• D. △H = q - P△V

Explanation: The change in enthalpy, ∆H, at constant pressure is equal to the sum of the heat absorbed or released, q, and the pressure-volume work…

• A. Endothermic
• B. Exothermic
• C. Spontaneous
• D. Non spontaneous

Explanation: When the enthalpy of the reactants is greater than the enthalpy of the products, it means that the reaction releases more energy than it…

• A. 𝚫H=𝚫E +P𝚫V
• B. 𝚫H=P𝚫V
• C. 𝚫H=𝚫E
• D. 𝚫H=0

Explanation: Option C is correct as ΔH=ΔE+PΔV and for a process involving solids and/or liqiuds, ΔV≅0. Therefore, 𝚫H=𝚫E.

• A. Water
• B. Kerosene oil
• C. Mercury
• D. rectified spirit

Explanation: Vapor pressure is determined by the strength of intermolecular forces, with weaker forces leading to higher vapor pressure.