All Free Chemistry MCQs with Answers

• A. Ethane
• B. Ethene
• C. Ethyne
• D. Methane

Explanation: Option A is incorrect as Alkanes have the highest bond length (of about 1.54 Angstrom).

• A. Ethene
• B. Ethane
• C. Ethyne
• D. Methane

Explanation: The bond length for a given pair of elements is a function of number and types of orbital overlaps.

• A. Polyvinyl polymer
• B. Polyvinyl Acetylene
• C. Neoprene
• D. Chloroprene

Explanation: The reaction of vinyl acetylene with HCl produces chloroprene. Chloroprene is a synthetic rubber that is used in a variety of…

• A. 2500°C
• B. 2600°C
• C. 2700°C
• D. 2800 °C

Explanation: When lime is heated with coke at about 2800°C in an electric furnace, calcium carbide is produced, which on hydrolysis yields acetylene.

• A. Ethylene
• B. Acetylene
• C. Acetone
• D. Ethene

Explanation: The first member of the Alkyne series is Ethyne which is also known as Acetylene in the common naming, having the formula C2H2.

• A. Red
• B. White
• C. Brown
• D. Pinkish

Explanation: Silver, in the form of Ag+, despite being a transition element, forms colourless compounds.

• A. Methane
• B. Ethane
• C. Propane
• D. Acetylene

Explanation: Carbide of alkaline earth metals are decomposed by water to form acetylene (C2H2). E.g: CaC2+ 2H2O ------ Ca(OH)2+ C2H2

• A. Benzene
• B. 1,3,5-cyclohexatriene
• C. Hexene
• D. Butane

Explanation: This option is correct since polymer is formed by combination of monomers.At 873 K when acetylene is passed through a red hot iron tube…

• A. Ozonolysis
• B. Hydroxylation
• C. Acetylide formation
• D. Kolbe's electrolysis

Explanation: Acetylene (C2H2) possesses two hydrogen atoms bonded to carbon atoms in its structure that exhibit acidic properties.

• A. 1
• B. 3
• C. 4
• D. 2

Explanation: Acetylene, C2H2, can be converted to ethane, C2H6, by a process known as hydrogenation.

• A. Benzene
• B. Ethane
• C. Ethene
• D. Ethyne

Explanation: Ethyne, also known as acetylene, is the most reactive among the given options due to its triple bond between the carbon atoms.

• A. It expands on heating
• B. It contracts on heating
• C. Both
• D. None

Explanation: If we take some water at 0 C and start heating it, we find that in the temperature range 0oC to 4oC, it contracts instead of expanding.on…

• A. 2.98˚C
• B. 3.98 ˚C
• C. 4 ˚C
• D. 4.98 ˚C

Explanation: The maximum density of water is at 4°C as there are two opposite effects that are in balance.

• A. 2°C
• B. 4°C
• C. 0°C
• D. <0°C

Explanation: When water is at 0 ° C , it takes a cage-like structure, and thus the volume increases which results in the density decrease.

• A. Ultraviolet radiation from sun causes a reaction that produces ozone
• B. Ozone hole is depletion in total amount of O
• C. A single chlorine free radical can destroy 10000 ozone molecules
• D. AII of above

Explanation: Ultraviolet radiations cause photochemical splitting of oxygen molecules in the stratosphere.

• A. N2
• B. N2O
• C. NO
• D. CO

Explanation: Nitrogen is an inert gas - meaning it doesn't chemically react with other gases - and it isn't toxic

• A. Smog
• B. Ozone
• C. Carbonic acid
• D. Chlorofluorocarbons

Explanation: CO2+H2O->H2CO3 This is how carbonic acid is formed from water.

• A. Petroleum
• B. Natural gas
• C. Automobiles
• D. Human beings

Explanation: There are many sources of unburned hydrocarbons. Unburned hydrocarbons (UHC) are typically an output of incomplete combustion due to…

• A. 1 - 3 %
• B. 2 - 5 %
• C. 1 - 9 %
• D. 3 - 8 %

Explanation: Organic sulfur is chemically bonded to the carbon atoms in the coal. The organic sulfur content of most coals ranges from 0.5% to about 2%.

• A. N2
• B. CO2
• C. O2
• D. He

Explanation: The most abundant naturally occurring gas is nitrogen (N2), which makes up about 78% of air.