All Free Chemistry MCQs with Answers

• A. Ice-cream
• B. Chewing gum
• C. Detergents
• D. Prefumes

Explanation: Vanillin is a popular flavoring agent used in various food products. Among the given options, ice-cream is the product that commonly…

• A. CH 2
• B. COOH
• C. C6H6
• D. Ç6H12011

Explanation: Benzene is an organic compound composed of six carbon atoms (C6) arranged in a hexagonal ring, with each carbon atom bonded to one…

• A. C6H6 + CH3CI
• B. C6H6
• C. C6H5C2H5
• D. C6H5CI & CH3Cl

Explanation: Toluene can be prepared by the Friedel-Crafts alkylation of benzene with methyl chloride (CH3Cl) in the presence of anhydrous aluminum…

• A. - NO2
• B. - NH2
• C. - OH
• D. - COOH

Explanation: The nitro group (NO2) is electron-withdrawing because it has a high electronegativity.

• A. -NH2
• B. -CHO
• C. -OH
• D. All of these

Explanation: Option B is correct.The -CHO group deactivates the benzene ring. Electron-withdrawing groups, like the -CHO group, withdraw electrons from…

• A. Carboxylic acid
• B. Aldehyde
• C. Ketone
• D. Alcohol and/or carbonyl compounds

Explanation: Catalytic oxidation of alkanes results in the formation of alcohols and/or carbonyl compounds.

• A. HCl bond is too strong to be broken homolytically
• B. Cl atom is not reactive enough to add on to a double bond.
• C. Cl combines with H to give back HCl
• D. HCl is a reducing agent

Explanation: Peroxides can act as radical initiators and generate highly reactive chlorine radicals (Cl•) from HCl.

• A. Intensity of UV light
• B. Concentration of X2 used
• C. Temperature
• D. All of these

Explanation: The extent of halogenation depends on all these factors. CH4+X2 → CH3X+HXCH4+2X2→ CH2X2 +2HXCH4+3X2→ CHX3+3HXCH4+4X2→ CX4 +4HX

• A. It takes place in the presence of less polar solvent (like alcohol)
• B. It takes place at high temperature
• C. It requires strong nueleophile (base)
• D. It takes place at low temperature

Explanation: Option D is correct. β-elimination reactions are generally favored at higher temperatures.

• A. H2C = CH2
• B. R - CH = CH - R
• C. R1R2C = CR3R4
• D. R1R2C = CHR4

Explanation: When a symmetrical alkene like R1R2C=CR3R4 is treated with hot concentrated KMnO4, it undergoes oxidative cleavage to produce two moles of…

• A. The headline read; 'Local Women Saves Geese'.
• B. The headline read, 'Local Women Saves Geese'.
• C. The headline read: 'Local Woman Saves Geese'.
• D. The headline read: "Local Women Saves Geese'

Explanation: This sentence correctly uses a colon to introduce the quotation, which is a common and appropriate use of the colon.

• A. The poor reader must be as confused as Media Watch about who has done which to whom.
• B. The poor reader must be as confused as Media Watch about which has done what to whom.
• C. The poor reader must be as confused as Media Watch about whom has done what to who.
• D. The poor reader must be as confused as Media Watch about who has done what to whom.

Explanation: This option is correct. "Who" is used correctly to refer to the subject (people), and "what" and "whom" are used correctly to refer to…

• A. Friedrich Reinitzer
• B. William crooks
• C. Bravis
• D. J J Thomson

Explanation: Friedrich ReinitzerExplanation: Friedrich Reinitzer, an Austrian botanist and chemist, is credited with the discovery of liquid crystals.

• A. sulphur
• B. Amorphous
• C. Crystalline
• D. Vitreous

Explanation: Only crystalline solids show all the properties of true solids.

• A. Anisotropy
• B. Isomorphism
• C. Allotropy
• D. Polymorphism

Explanation: When an element exists in more than one crystalline forms, it is known as allotropy.

• A. Anisotropy
• B. Isomorphism
• C. Allotropy
• D. Polymorphism
• E. Option C and D

Explanation: Allotropy specifically refers to the existence of an element in two or more different structural forms when they are in the same physical…

• A. Canal rays
• B. Cathode rays
• C. Both a and b
• D. None

Explanation: Positive rays are called canal rays which are streams of positively charged particles found in cathode ray tubes.

• A. Alpha particle
• B. Neutron
• C. Electron
• D. Proton
• E. All of these

Explanation: A neutron has no net electric charge, so it is electrically neutral, whereas an alpha particle and proton are positive and an electron is…

• A. Cu (Copper)
• B. Ag (Silver)
• C. Pt (Platinum)
• D. None

Explanation: Platinum is often used as an inert electrode because it doesn't undergo significant chemical reactions during electrochemical processes.

• A. N (Nitrogen)
• B. Cr (Chromium)
• C. S (Sulfur)
• D. Mn (Manganese)

Explanation: Manganese (Mn) exhibits a wide range of oxidation states, including +2, +4, +6, and +7.