All Free Chemistry MCQs with Answers
Every Chemistry question in the bank, across all chapters, each with the correct answer and a written explanation. Free and unlimited, with no account needed.
13,720 questions · page 486 of 686
- A. Calcined gypsum
- B. Sea shells
- C. Dolomite
- D. A marble statue
Explanation: The correct answer is Calcined gypsum. Gypsum is CaSO4 . 2H2O, which does not contain CaCO3. Sea shells contain calcium carbonate (CaCO3).
Correct answer: Calcined gypsum- A. Mg
- B. Ba
- C. Ca
- D. Be
Explanation: Beryllium (Be) is the correct metal in this scenario. Beryllium sulfate (BeSO4) is water-soluble due to its high solvation energy, unlike…
Correct answer: Be- A. Li+
- B. Na+
- C. K+
- D. Rb+
Explanation: The ionic mobility of an ion in aqueous solution is inversely related to the extent of hydration.
Correct answer: Rb+9704. Cryolite is :
- A. Calcium fluoride
- B. Potassium hexafluoroaluminate(III)
- C. Basic magnesium carbonate
- D. Sodium hexafluoroaluminate(III)
Explanation: The correct answer is Option D: Sodium hexafluoroaluminate(III). Cryolite is an ore of sodium with the chemical formula Na3[AlF6], making…
Correct answer: Sodium hexafluoroaluminate(III)- A. Cu2O + FeS
- B. FeSiO3
- C. CuFeS2
- D. Cu2S + FeO
Explanation: In the extraction of copper from its ores, iron is a common impurity that needs to be removed during the smelting process.
Correct answer: FeSiO3- A. Reduction
- B. Oxidation
- C. Reduction followed by oxidation
- D. Oxidation followed by reduction
Explanation: Oxidation followed by Reduction: This process involves the oxidation of carbon to carbon dioxide, followed by reduction steps to extract…
Correct answer: Oxidation followed by reduction- A. Cuprite
- B. Chalcoite
- C. Chalcopyrite
- D. both (b) and (c)
Explanation: Chalcocite and Chalcopyrite are the correct answers as they are copper ores that contain both sulfur and copper.
Correct answer: both (b) and (c)9708. Formula of Felspar is :
- A. K2O. Al2O3. 6 SiO2
- B. K2O3. Al2O3.6Si2.O2.2H2O
- C. Al2O3. 2SiO2.2H2O
- D. 3MgO.4SiO2.H2O
Explanation: The correct formula for feldspar is K2O.Al2O3.6SiO2. Feldspar is primarily composed of aluminum silicates with potassium oxide and silicon…
Correct answer: K2O. Al2O3. 6 SiO29709. Flux is used to remove :
- A. Silica
- B. Metal oxide
- C. All impurities from ores
- D. Silica and undesirable metal oxide
Explanation: Flux is commonly used to remove both silica and undesirable metal oxides from ores during metallurgical processes.
Correct answer: Silica and undesirable metal oxide- A. Oxidation of Fe ore
- B. Reduction of Fe ore
- C. Formation of slag
- D. Purification of Fe formed
Explanation: Limestone is used in the formation of slag during the extraction of iron from its ore in a blast furnace.
Correct answer: Formation of slag- A. Cupellation
- B. Poling
- C. Van Arkel
- D. Zone refining
Explanation: The equation given involves the purification of titanium (Ti) using the Van Arkel process, which is also sometimes referred to as the…
Correct answer: Van Arkel- A. Volatile stable compound
- B. Volatile unstable compound
- C. Non volatile stable compound
- D. None of the above
Explanation: The Van Arkel method, also known as the iodide process, is a purification technique used for certain reactive metals like titanium and…
Correct answer: Volatile stable compound9713. Calamine is an ore of :
- A. Hg
- B. Zn
- C. Cd
- D. Ca
Explanation: Calamine is a mineral that is a significant source of zinc. It is primarily composed of zinc carbonate (ZnCO3) along with variable amounts…
Correct answer: Zn- A. Adsorption
- B. Absorption
- C. Coagulation
- D. Sedimentation
Explanation: Froth flotation is a widely used process for separating valuable minerals from gangue (unwanted material) in ore minerals.
Correct answer: Adsorption- A. ZnO
- B. Fe2O3
- C. PbO
- D. Al2O3
Explanation: Option D is correct.Aluminum oxide (Al2O3) cannot be reduced to metal by carbon.
Correct answer: Al2O3- A. Froth flotation on adding NaCN
- B. Electromagnetic separation
- C. Handpicking
- D. All of these
Explanation: Option A is correct. Froth flotation leverages the difference in hydrophobic properties to separate ZnS and PbS effectively.
Correct answer: Froth flotation on adding NaCN- A. Cu
- B. Fe
- C. Hg
- D. F
Explanation: Option A is correct because copper is indeed extracted from its ores using the cyanide process.
Correct answer: Cu- A. Reduction
- B. Oxidation
- C. Reduction followed by oxidation
- D. Oxidation followed by reduction
Explanation: The correct answer is Option D: Oxidation followed by reduction. In the production of steel from haematite, the process begins with…
Correct answer: Oxidation followed by reduction- A. Electromagnetic method
- B. Leaching with NaCN method
- C. Froth floatation process
- D. Both A and C
Explanation: Option C is correct. Copper pyrite ore is concentrated by the froth flotation process.
Correct answer: Froth floatation process- A. Sodium and iron
- B. Sodium and aluminium
- C. Aluminium, iron and sodium
- D. Sodium, iron, cadmium and aluminium
Explanation: Option B is correct. The process described involves the precipitation of Cu2+ and Cd2+ ions as sulfides when H2S is passed in the presence…
Correct answer: Sodium and aluminium