All Free Chemistry MCQs with Answers

• A. Na
• B. K
• C. Rb
• D. Li

Explanation: Lithium is the alkali metal that reacts the slowest with water among the options given.

• A. Mg
• B. Ca
• C. Rb
• D. Sr

Explanation: Magneisum has the smallest shielding effect in the given elements, because as you move alonga group(from top to bottom in the periodic…

• A. Electronegativity
• B. Thick, small electronic cloud
• C. Seven electrons in outermost shell
• D. Higher ionization energy

Explanation: Fluorine has less electron affinity compared to bromine primarily due to its small atomic size and the associated compact 2p subshell…

• A. HClO₄
• B. HClO₃
• C. HClO
• D. HClO₂

Explanation: The lower the oxidation state of halogen in an oxyacid, the stronger the oxidizing ability, because it can accept electrons to reach a…

• A. Al
• B. Ca
• C. Mg
• D. Cu

Explanation: The metal that is extracted from bauxite is A. Al (aluminum).

• A. 1s2 2s2 2p3
• B. 1s2 2s2 2p4
• C. 1s2 2s2 2p1
• D. 1s2 2s2 2p2

Explanation: The element that belongs to group IIIA (Group 13) of the periodic table is boron (B), so the correct option is C: 1s2 2s2 2p1.

• A. Insoluble
• B. Soluble in water to give neutral solution of ph 7
• C. Soluble in water to give acidic solution of ph 1
• D. Soluble in water to give alkaline solution of ph 14

Explanation: The correct description for the metal chlorides formed when alkali metals react with chlorine gas is B.

• A. 12 moles of oxygen
• B. 15 moles of oxygen
• C. 18 moles of oxygen
• D. 21 moles of oxygen

Explanation: Option C is correct. The balanced chemical equation is: 2 KClO3(l) + heat → 2 KCl(s) + 3 O2(g).

• A. SO2 oxidizes KMnO4
• B. SO2 reduces KMnO4
• C. KMnO4 is inert in acidic medium
• D. SO2 can't undergo redox reaction

Explanation: Option B is correct as SO2 is a strong reducing agent and KMnO4 is a strong oxidising agent.

• A. The solubility product for Mg(OH)2 is lower than that for Ca(OH)2
• B. The atomic radius of Mg is smaller than that of Ca.
• C. Magnesium is more reactive than calcium.
• D. Calcium has a higher ionization energy than magnesium.

Explanation: This is the correct answer. As discussed previously, solubility product (Ksp) plays a crucial role in determining the extent to which an…

• A. Calcium chloride
• B. Sodium chloride
• C. Potassium chloride
• D. Magnesium chloride

Explanation: This is the correct answer. In the Down's process, a small amount of calcium chloride (CaCl2) is added to molten sodium chloride (NaCl) to…

• A. Mg(OH)2
• B. Mg(OH)
• C. MOH
• D. Mg(OH)3

Explanation: When magnesium (Mg) reacts with two molecules of water (H2O), it forms magnesium hydroxide (Mg(OH)2).

• A. Li: Red
• B. Na: Lilac
• C. K: Red
• D. Cs: Yellow

Explanation: Flame tests are used to identify alkali metals based on the characteristic colors they produce when burned:- Lithium (Li): Red- Sodium…

• A. Boron has a higher electronic configuration than Beryllium
• B. Atomic radius of Beryllium is smaller than Boron
• C. Beryllium has a stable electronic configuration
• D. Boron has a smaller atomic number than Beryllium

Explanation: Beryllium has a stable electronic configuration - Correct. Beryllium has a fully filled 2s orbital, which is more stable and requires more…

• A. Mg
• B. Ca
• C. Na
• D. Be

Explanation: Be - Correct. Beryllium does not react with water under normal conditions due to the formation of an oxide layer that prevents further…

• A. ns²np⁵
• B. ns²np⁶
• C. ns¹np⁵
• D. ns²np³

Explanation: ns²np⁶ - Correct. Halide ions gain one electron to achieve a full octet, resulting in this configuration.

• A. Have powerful reducing agents
• B. Have positive reduction potential
• C. Cannot displace H₂ from dilute acids
• D. Lies below SHE in electrochemical series

Explanation: Have powerful reducing agents - Incorrect. Coinage metals (Cu, Ag, Au) are not strong reducing agents; they have low reactivity and tend…

• A. K2CrO4
• B. MnO2
• C. K2Cr2O4
• D. KMnO4
• E. O2

Explanation: The correct answer is option D: KMnO4. When potassium permanganate (KMnO4) is oxidized by chlorine gas (Cl2), the product obtained is…

• A. No. of positron
• B. No. of neutron
• C. Nuclear charge
• D. No. of electron
• E. Atomic size

Explanation: The correct answer is option (c): Nuclear charge. Ionization energy is the energy required to remove an electron from an atom or ion in…

• A. Na
• B. K
• C. Rb
• D. Li

Explanation: Sodium, potassium and rubidium are all in the same group, but sodium is larger than lithium, potassium is larger than sodium and rubidium…