[linkamfai]

Why silane burns in contact with air, whereas methane requires a spark before it will combust

[Borek]

You have to show your attempts at solving the question to receive help. This is a forum policy.

Have you heard a term "activation energy"?

[linkamfai]

You have to show your attempts at solving the question to receive help. This is a forum policy.

Have you heard a term "activation energy"?

I'm sorry for against the policy.
Is that any reason(s), other than electronegative caused the different in activation energy?

[Corribus]

Flammability and pyrophoricity are complex properties and often are affected by factors not directly related to the compound itself (impurities, etc.). But a simplistic explanation can be had by considering that the combustion of either silane or methane requires in some way breaking an Si-H or C-H bond, and the rate of the reaction will depend on how much energy it takes to do this. Si-H bond is significantly weaker than C-H bond (for the silane/methane reactions, I find the bond enthalpy to be ~ 335 kJ/mol and ~ 432 kJ/mol, respectively). Can you think of a plausible reason why?