James Chadwick bombarded beryllium with alpha particles and discovered: MCQ with Answer and Explanation

James Chadwick bombarded beryllium with alpha particles and discovered:
A. Neutron
B. Electron
C. Positron
D. Proton
Answer: Option A
Solution (By JKExamLibrary)
Chadwick (1932) produced highly penetrating neutral radiation by bombarding Be with α-particles, identified as neutrons. Reaction: ⁹Be + ⁴He → ¹²C + ¹n.

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Practice More chemistry Questions

Question #1
Boyle's law states that at constant temperature, the pressure of a gas is inversely proportional to its:
A. Density
B. Temperature
C. Mass
D. Volume

Correct Answer: Option D


Explanation:
Boyle's law: PV = constant (at fixed T and n). So P ∝ 1/V. If volume is doubled, pressure halves. Charles' law relates V and T; Graham's law relates diffusion rate to molar mass.

This question belongs to: Science chemistry
Question #2
The scientist who discovered the neutron was:
A. James Chadwick
B. Ernest Rutherford
C. J. J. Thomson
D. Niels Bohr

Correct Answer: Option A


Explanation:
James Chadwick discovered the neutron in 1932 by bombarding beryllium with alpha particles, producing a neutral radiation that he identified as neutrons. Rutherford had predicted the existence of a neutral particle in 1920. Chadwick's discovery explained isotopes' mass differences. Neutron: mass ≈ 1.00866 u, no charge. It is stable inside the nucleus but decays (half-life ~10 min) when free.

This question belongs to: Science chemistry
Question #3
In the reaction 2FeCl₃ + H₂S → 2FeCl₂ + 2HCl + S, the reducing agent is:
A. FeCl₂
B. H₂S
C. HCl
D. FeCl₃

Correct Answer: Option B


Explanation:
H₂S is oxidized (S²⁻ → S, loss of electrons), so it acts as the reducing agent. FeCl₃ is reduced (Fe³⁺ → Fe²⁺) and acts as oxidizing agent. The substance oxidized is the reducing agent.

This question belongs to: Science chemistry