All Free Chemistry MCQs with Answers

• A. Alkali
• B. Alkaline earth
• C. s block elements
• D. P block elements

Explanation: Group 1A and 11A elements are known as s-block elements. This is because their valence electrons occupy the s-orbital.

• A. Decreases down the group
• B. Increases down the group
• C. Remains same
• D. None of these

Explanation: The basic character of alkali metal oxides increases down the group. This is because the metallic character of the elements increases down…

• A. Na
• B. Al
• C. Fe
• D. Ca

Explanation: Sodium (Na) is a highly reactive alkali metal that reacts rapidly with water at room temperature to produce sodium hydroxide (NaOH) and…

• A. Ions
• B. Hydrogen gas
• C. Water
• D. None of these

Explanation: The fire produced when alkali metals react with water is due to the ignition of the hydrogen gas released during the reaction.

• A. White
• B. Pink
• C. Blue
• D. Green

Explanation: Epsom salt (MgSO₄.7H₂O) is a white crystalline solid. It is commonly used as a bath salt, laxative, and fertilizer.

• A. Charge on the nucleus
• B. Distance between nucleus and outer most electron
• C. Size of the atom
• D. None of these

Explanation: As you move down the group, the atomic size increases because additional electron shells are added.

• A. Feldspar
• B. Limestone
• C. Diamond
• D. None of these

Explanation: Limestone is a sedimentary rock composed primarily of calcium carbonate (CaCO₃).

• A. Spodumene
• B. Rock salt
• C. Carnallite
• D. Alunite

Explanation: Spodumene is a lithium aluminum silicate mineral with the formula LiAlSi₂O₆.

• A. MgSO4.7H2O
• B. MgCO3
• C. MgCO3.CaCO3
• D. Mg(SiO3)4

Explanation: Epsom salt is a hydrated magnesium sulfate with the chemical formula MgSO₄.7H₂O.

• A. Nitrogen
• B. Phosphorous
• C. Oxygen
• D. Sulphur

Explanation: Phosphorous (P) is a highly reactive nonmetal and does not occur in its free state. It is found in various minerals like phosphate rocks.

• A. NO
• B. NH4
• C. N₂O
• D. NO3

Explanation: Laughing gas is the common name for nitrous oxide (N₂O). It is a colorless, odorless gas that is used as an anesthetic and as an oxidizer…

• A. SO₂
• B. SCl₂
• C. H₂SO₄
• D. H₂SO₃

Explanation: The oxidation state of S in H₂SO₄ is +6, which is the highest oxidation state of sulfur.In SO₂ the oxidation state of S is +4.In SCl₂ the…

• A. Oxygen
• B. Sulphur
• C. Both
• D. None of these

Explanation: Allotropes are different structural modifications of the same element in the same physical state.

• A. 7
• B. 8
• C. 6
• D. 9

Explanation: Rhombic sulphur is one of the allotropic forms of sulphur. It has a crystalline structure where eight sulphur atoms are linked together in…

• A. Paint
• B. Textile
• C. Rubber
• D. Aluminum

Explanation: Sulfuric acid (H₂SO₄) is a highly corrosive strong acid that is widely used in many industries.

• A. N
• B. P
• C. As
• D. Sb

Explanation: Allotropes are different structural modifications of the same element in the same physical state. Nitrogen (N) does not exhibit allotropy.

• A. It is relatively unstable than O₂
• B. It provides an extra oxygen atom then O₂
• C. It provides Nascent Oxygen
• D. All of above

Explanation: Ozone (O₃) is a more powerful oxidizing agent than oxygen (O₂) due to the following reasons:a) It is relatively unstable than O₂: Ozone is…

• A. 2
• B. 3
• C. 1
• D. Several

Explanation: Nitrogen forms a variety of oxides with different oxidation states. Some common examples include:Nitrous oxide (N₂O)Nitric oxide…

• A. Sodium
• B. Iron
• C. Sulphur
• D. Potassium

Explanation: Vulcanization is the process of adding sulfur to natural rubber to improve its strength, elasticity, and durability.

• A. Oxygen
• B. Hydrogen
• C. Carbon dioxide
• D. Nitrogen

Explanation: Air is composed of various gases, and nitrogen makes up the largest portion, roughly 78%.