All Free Chemistry MCQs with Answers

• A. KAlSi3O8
• B. KCl·MgCl2·6H2O
• C. KCl
• D. KCl·Al2O3·2H2O

Explanation: Carnallite is a hydrated potassium magnesium chloride mineral with the chemical formula KCl·MgCl2·6H2O.

• A. Xy
• B. Xy2
• C. X1y
• D. Xy3

Explanation: The valence shell configuration of x indicates that it belongs to group I-A (the alkali metals) while the valence configuration of y…

• A. Li2O
• B. Li2N
• C. Li2O2 + Li2CO3
• D. Both (a) & (b)

Explanation: Lithium reacts with the oxygen in the air to form lithium oxide (Li2O) and with nitrogen to form lithium nitride (Li3N).

• A. Cs
• B. Rb
• C. K
• D. All of the above

Explanation: Alkali metals form oxides (O²⁻), peroxides (O₂²⁻), or superoxides (O₂⁻) depending on their size.Larger cations stabilize larger anions:Li…

• A. B
• B. Na
• C. K
• D. Mg

Explanation: Boron (B) is more electronegative compared to the other elements listed (Na, K, and Mg).

• A. Mg (OH)
• B. MgO
• C. MgO 10H2O
• D. MgO2

Explanation: Metals react with water under different conditions and produce metal oxide or hydroxide and liberate hydrogen gas.

• A. Na
• B. Ca
• C. Sr
• D. Ba

Explanation: A flame test is an analytical procedure used by chemists to detect the presence of particular metal ions, based on the color of the flame…

• A. calcium
• B. Potassium
• C. iron
• D. magnesium

Explanation: The Mohs scale of mineral hardness is used to compare the scratch resistance of different minerals.

• A. MgO and clay
• B. MgCO3 and clay
• C. MgSO4 and clay
• D. MgCO3 and CaCO3

Explanation: Refractory materials can withstand high temperatures. Refractory bricks are used in lining furnaces, kilns, fireboxes, and fireplaces.

• A. Sodium
• B. Potassium
• C. Strontium
• D. Calcium

Explanation: The correct answer is Strontium because it imparts a crimson red color to the flame when subjected to a flame test.

• A. CaSO4
• B. CaCO3
• C. CaCl2
• D. MgCO3

Explanation: In this reaction, dilute hydrochloric acid reacts with a carbonate compound, releasing carbon dioxide gas (CO2).

• A. Li+
• B. Mg2+
• C. Cs+
• D. Be2+

Explanation: Polarizability refers to the ability of a cation to distort the electron cloud of an anion in an ionic compound and the anionic cloud is…

• A. Diamond
• B. Graphite
• C. Coal
• D. Charcoal

Explanation: Diamond: Diamond is the inert form of carbon. It is a crystalline structure where each carbon atom is bonded to four neighboring carbon…

• A. Hg
• B. Pb
• C. Fe
• D. Sn

Explanation: Pb (Lead): If pellets containing lead (Pb) remain in the body, they can cause lead poisoning, which can result in neurological…

• A. CH4
• B. C2H6
• C. C3H4
• D. C4H20

Explanation: The hydrolysis of Al4C3 (aluminum carbide) produces methane gas. The chemical equation for the hydrolysis reaction of Al4C3 can be…

• A. Soda glass
• B. Water glass
• C. Jinna glass
• D. Pyrex glass

Explanation: Sodium silicate is commonly known as water glass, or soluble glass. It gets its name because it is essentially glass (silicon dioxide) in…

• A. Slow and exothermic
• B. Fast and exothermic
• C. Slow and endothermic
• D. Fast and endothermic

Explanation: The correct answer is that the conversion of carbonate to urea is slow and endothermic.

• A. Bauxite
• B. Borax
• C. Carborundum
• D. Colemanite

Explanation: The compound Na2B4O7 10 H2O is known as Borax. It is a naturally occurring mineral and a common household cleaning agent.

• A. PbO + 4NaOH →Pb (OH)4 + 2 Na2O
• B. PbO + 2NaOH + H2O →Na2 [Pb(OH)4]
• C. PbO + NaOH + H2O →Na [Pb(OH)3]
• D. PbO + 4NaOH + H2O →Na4 [Pb(OH)6]

Explanation: When PbO hydrolyses in water and NaOH, Na2 [Pb(OH)4 is formed, thus B is correct.

• A. Copper and zinc
• B. Copper and tin
• C. Zinc and tin
• D. Chromium and Tin

Explanation: Bronze is an alloy traditionally composed of copper and tin. Modern bronze is typically 88 percent copper and about 12 percent tin.