Properties of bituminous coal: Which statements about bituminous coal are generally true?

Introduction:
Coal rank strongly influences ignition, flame appearance, and coking behavior. Bituminous coals are mid-rank coals used widely for power and metallurgical coke production. This question checks basic recognition of their combustion and coking traits.

Given Data / Assumptions:

• Anthracite is a higher-rank coal with low volatiles and higher ignition temperature.
• Many bituminous coals are coking (though not all); coking depends on rank and petrography.
• Volatile matter in bituminous coal yields luminous, smoky flames.

Concept / Approach:
Bituminous coal contains more volatile matter than anthracite, so it ignites more readily and burns with a smoky yellow flame due to soot precursors. Many bituminous coals possess the plasticity needed for coking, making them suitable for metallurgical coke when blended appropriately.

Step-by-Step Solution:
(a) is false: anthracite, not bituminous, is harder to ignite.(b) is generally true: numerous bituminous coals are coking.(c) is true: higher volatiles produce luminous, smoky flames.Hence, (d) “both (b) and (c)” is correct.

Verification / Alternative check:
Proximate analysis (volatile matter) and coking tests (Gieseler fluidity, Roga index) corroborate these characteristics.

Why Other Options Are Wrong:

• (a) reverses the ignition ease; (e) conflicts with true statements (b) and (c).

Common Pitfalls:
Assuming all bituminous coals are coking; some are non-coking and require blending.

Final Answer:
both (b) and (c)