Q58 · CSIR NET Chemistry, June 2013
Paper: CSIR NET June 2013 · Subject: Inorganic Chemistry · Chapter: Nuclear Chemistry · Topic: Nuclear Reactions Q Value · Marks: 2 · Difficulty: Easy
For the nuclear reactions.
\[ \text{(A)}\quad {}_4^8\mathrm{Be} \rightarrow 2\,{}_2^4\mathrm{He} \]
\[ \text{(B)}\quad {}_{36}^{80}\mathrm{Kr} \rightarrow 2\,{}_{18}^{40}\mathrm{Ar} \]
(Given masses: $^8\mathrm{Be} = 8.005300$, $^4\mathrm{He} = 4.002603$ and ${}_{36}^{80}\mathrm{Kr} = 79.81638$, ${}_{18}^{40}\mathrm{Ar} = 39.96238$) The correct statement is:(a)(A) and (B) are both spontaneous fission processes.
(b)(A) is spontaneous fission but (B) is not.
(c)(B) is spontaneous fission but (A) is not
(d)Both (A) and (B) are not spontaneous fission processes.
Answer
Answer: D ✓ checked by 4AB · confidence high
The source book printed B; on checking, D is correct — see the explanation.
Explanation
⁸Be (8.005300) is heavier than 2 × ⁴He (8.005206), so it splits spontaneously; ⁸⁰Kr (79.81638) is lighter than 2 × ⁴⁰Ar (79.92476), so that fission is impossible. (A) spontaneous, (B) not.
Study loop for Nuclear Chemistry