Question
What is average atomic mass of chlorine if its two isotopes Cl ^ 35 and Cl ^ 37 exists in relative abundance of 75\% and 25\% respectively ?
MHT CET
Chemistry
Some Basic Concepts of Chemistry
2026
MHT CET 2026 (20 April Shift 1)
MHT CET Chemistry Question (2026) — Solution
Options
- A. 35.0
- B. 35.5
- C. 37.0
- D. 37.5
Answer
B. 35.5
Step-by-step solution
Average atomic mass is calculated using the formula: Average atomic mass = m_1 p_1 + m_2 p_2 100 where m_1 and m_2 are the atomic masses of the isotopes, and p_1 and p_2 are their respective percentage abundances. Substituting the given values: Average atomic mass = 35 75 + 37 25 100 Average atomic mass = 2625 + 925 100 Average atomic mass = 3550 100 = 35.5 Answer: 35.5
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