The number of pentagons in C₆₀ and trigons (triangles) in white phosphorus, respectively, are :

For the reaction of H₂ with I₂, the rate constant is 2.5 × 10^–4 dm³ mol^–1s^–1 at 327°C and 1.0 dm³ mol^–1 at 527°C. The activation energy for the reaction, in kJ mole^–1 is : (R = 8.314 JK^–1 mol^–1 )

A hydrated solid X on heating initially gives a monohydrated compound Y. Y upon heating above 373 K leads to an anhydrous white powder Z. X and Z, respectively, are :

The major product 'Y' in the following reactions is :