All Free Chemistry MCQs with Answers

• A. Ti
• B. Zr
• C. Al
• D. All of these

Explanation: The correct answer is Option C: Al. The Van Arkel process can extract ultrapure metals like Ti and Zr, but it cannot extract Al.

• A. First increases then decreases
• B. First decreases then increases
• C. Continuously decreases
• D. Continuously increases

Explanation: The correct answer is that the density of alkaline earth metals first decreases and then increases as you move down the group.

• A. Option A: Linear structure
• B. Option B: Open-book structure
• C. Option C: Planar structure
• D. Option D: Tetrahedral structure

Explanation: The correct structure of H2O2 is an open-book structure. This means that the molecule is not linear or planar, but instead has a dihedral…

• A. Mg
• B. Be
• C. Ca
• D. Ba

Explanation: Beryllium does not react with water, even at red-hot temperatures. This is because beryllium has very high ionization energy, which makes…

• A. 1s2,2s2, 2p6, 3s1, 3p6, 4s2
• B. Is2, 2s2, 2p6, 3s2, 3p6, 4s2
• C. 1s2, 2s2, 2p6, 3s2,3p6, 4s1
• D. Is2, 2s2, 2p6, 3s2, 3p5, 4s1

Explanation: 1s2, 2s2, 2p6, 3s2,3p6, 4s1 This is the correct electronic configuration as it potassium has 19 electron and all orbitals are filled in…

• A. Al
• B. Na
• C. K
• D. Mg

Explanation: Aluminium on reaction with oxygen forms Al2O3 which is an amphoteric oxide.

• A. Ba(NO3)2 and Ca(OH)2
• B. BaSO4 and CaCO3
• C. CaCO3 and MgSO4
• D. Ca(OH)2 and MgCO3

Explanation: The reaction between dilute hydrochloric acid and BaSO4 is: BaSO4 + 2HCl → BaCl2 + SO2 + H2O BaSO4 is insoluble in dilute hydrochloric…

• A. Lead
• B. Tin
• C. Graphite
• D. Silicon

Explanation: Britannia metal is an alloy composed of Tin (Sn), Antimony (Sb), and Copper (Cu).

• A. Si
• B. Ge
• C. Se
• D. As

Explanation: The correct answer is Option D: As. Arsenic (As) is not a semiconductor in its elemental form.

• A. Electrical conductivity
• B. Boiling point
• C. Ionization energy
• D. Atomic size

Explanation: The correct answer is Option A: Electrical conductivity. The graph provided illustrates the trend for electrical conductivity…

• A. Si (OH)₄, NaOH, H₃PO₄
• B. HClO₄, H₂SO₄, Ca (OH)₂
• C. Si(OH)₄, HCl, H₃PO₄
• D. Mg (OH)₂, H₃PO₄, HClO₄

Explanation: The correct answer is Option C: Si(OH)₄, HCl, H₃PO₄. This combination contains HCl, which is a strong acid, contributing to the acidic…

• A. NaNO3
• B. KNO3
• C. Na2B4O7 . 10H2O
• D. Na₂B₄O₇

Explanation: Option a is the correct chemical formula for Chile saltpeter. It consists of sodium (Na) and nitrate (NO3) ions.

• A. Na+
• B. Cs+
• C. Ba+2
• D. Mg+2

Explanation: Mg²⁺, also has a double positive charge like Ba²⁺, but magnesium ions are smaller in size compared to barium ions.

• A. Fe
• B. Cu
• C. Zn
• D. Diamond

Explanation: Iron is a metal with a hardness ranging from 4 to 5 on the Mohs scale, depending on its purity and crystal structure.

• A. Cs
• B. K
• C. Na
• D. Li

Explanation: Cesium (Cs) is the most reactive alkali metal because it has the largest atomic radius and the lowest ionization energy among the alkali…

• A. Zn
• B. Ba
• C. Sr
• D. Ca

Explanation: Zinc does not give a characteristic flame test because its flame color is not distinctive.

• A. Toluene
• B. Alcohol
• C. Benzene
• D. Kerosene oil

Explanation: Alcohol is correct because alcohols can react with sodium metal, posing a safety hazard.

• A. Ca and Ba
• B. Mg and Al
• C. Ca and Mg
• D. Na

Explanation: Dolomite is a double carbonate mineral composed of calcium (Ca) and magnesium (Mg). It has the chemical formula CaMg(CO3)2.

• A. [Ar] 3d10 4s2
• B. [Ne] 3d23p2
• C. [Ar] 4s2
• D. [Ar] 3d10 4s1

Explanation: Alkaline earth metals belong to Group 2 of the periodic table, which includes elements like beryllium (Be), magnesium (Mg), calcium (Ca)…

• A. CaSO4 . 2H2O
• B. CaSO4 .1/2 H2O
• C. CaSO4
• D. MgSO4 . 7H2O

Explanation: It represents the anhydrous form of calcium sulfate, which is dead burnt gypsum.