The discovery of the electron was done by: MCQ with Answer and Explanation

The discovery of the electron was done by:
A. Niels Bohr
B. J. J. Thomson
C. James Chadwick
D. Ernest Rutherford
Answer: Option B
Solution (By JKExamLibrary)
J.J. Thomson discovered the electron in 1897 using cathode ray tubes and determined its e/m ratio. Rutherford discovered the nucleus; Chadwick discovered neutron; Bohr proposed quantized model.

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Practice More chemistry Questions

Question #1
Which metal is used in the thermal process for welding railway tracks?
A. Zinc
B. Copper
C. Aluminium
D. Iron

Correct Answer: Option C


Explanation:
Thermite reaction: Fe₂O₃ + 2Al → 2Fe + Al₂O₃ + heat. Molten iron produced fills the gap between rails. Aluminium is the reducing agent.

This question belongs to: Science chemistry
Question #2
The process of converting unsaturated hydrocarbons into saturated hydrocarbons by adding hydrogen is called:
A. Hydrogenation
B. Polymerization
C. Halogenation
D. Substitution

Correct Answer: Option A


Explanation:
Hydrogenation is the addition of hydrogen to unsaturated compounds (like alkenes or alkynes) in the presence of a catalyst (like Ni, Pd, or Pt) to form saturated compounds (alkanes). For example, ethene + H₂ → ethane. This process is widely used in the food industry to solidify vegetable oils.

This question belongs to: Science chemistry
Question #3
Which of the following contains a coordinate bond?
A. NaCl
B. H₂O
C. NH₃
D. O₃

Correct Answer: Option D


Explanation:
Ozone (O₃) has a coordinate bond (dative bond). One oxygen atom donates a lone pair to another oxygen atom. The Lewis structure shows O=O⁺–O⁻ or resonance. NaCl is ionic; H₂O has polar covalent bonds; NH₃ has ordinary covalent bonds (though it can donate a lone pair to form coordinate bond in NH₄⁺).

This question belongs to: Science chemistry