2025 · Paper 2 · Chemistry
Question 15
The printed question, the official key, and each model’s JSON answer plus the reasoning it wrote.
ChemistryPaper 2Numerical
Q15
Official 7.5 – 7.8
Model answers
Claude Fable 5.1
Anthropic
Correct4 / 4
7.73
Claude Fable 5.1 reasoning
[Mn(Br)₆]³⁻: Mn is in +3 oxidation state, d⁴. Br⁻ is a weak field ligand → high spin, t₂g³ e_g¹, 4 unpaired electrons. μ = √(4×6) = √24 ≈ 4.90 B.M. [Mn(CN)₆]³⁻: Mn³⁺, d⁴. CN⁻ is a strong field ligand → low spin, t₂g⁴, 2 unpaired electrons. μ = √(2×4) = √8 ≈ 2.83 B.M. Sum = 4.90 + 2.83 = 7.73 B.M.
GPT 6 Astra
OpenAI
Correct4 / 4
7.73
GPT 6 Astra reasoning
No written reasoning was returned for this item.
GPT 5.6 Luna
OpenAI
Correct4 / 4
7.73
GPT 5.6 Luna reasoning
No written reasoning was returned for this item.