Question
The d -electron configurations of Cr ^ 2+ , Mn ^ 2+ , Fe ^ 2+ and Co ^ 2+ are d^ 4 , d^ 5 , d^ 6 and d^ 7 respectively. Which one of the following will exhibit the lowest paramagnetic behaviour? (Atomic no. Cr =24, Mn =25, Fe =26, Co =27)
BITSAT
Chemistry
Coordination Compounds
2020
BITSAT 2020
BITSAT Chemistry Question (2020) — Solution
Options
- A. [ Co ( H _ 2 O )_ 6 ]^ 2+
- B. [ Cr ( H _ 2 O )_ 6 ]^ 2+
- C. [ Mn ( H _ 2 O )_ 6 ]^ 2+
- D. [ Fe ( H _ 2 O )_ 6 ]^ 2+
Answer
A. [ Co ( H _ 2 O )_ 6 ]^ 2+
Step-by-step solution
Since Co ^ 2+ has lowest no. of unpaired electrons hence lowest paramagnetic behaviour is shown by [ Co ( H _ 2 O )_ 6 ]^ 2+
Related: Chemistry — Coordination Compounds · All PYQ Banks