Choose the INCORRECT statement.

Correct option is B

Introduction

Pyrolysis is the thermal decomposition of organic material in the absence of oxygen, producing char, liquid (bio-oil), and gaseous products. Understanding its energy requirements and outputs is central to waste-to-energy and biochar applications.

Information Booster

Pyrolysis is fundamentally an endothermic process, not exothermic. It requires a continuous external supply of heat to drive the thermal breakdown of complex organic molecules into simpler char, condensable vapours, and non-condensable gases in an oxygen-free (or oxygen-starved) environment.

Because the bonds in the feedstock must be broken by absorbed thermal energy, heat has to be supplied throughout — typically at 300–900 °C.

This contrasts sharply with combustion or incineration, which are exothermic and release net energy. Labelling pyrolysis as "primarily exothermic" reverses its true thermal character, making statement the incorrect one and hence the answer.

(Some secondary reactions within pyrolysis can be mildly exothermic, but the overall process is heat-demanding.)

Additional knowledge

 Pyrolysis is used to make charcoal and coke — Correct. Charcoal is produced by the slow pyrolysis of wood, and coke by the destructive distillation (pyrolysis) of coal  both classic, long-standing pyrolytic processes.
· Residue of incomplete organic pyrolysis improves soil texture and nutrient status — Correct. The solid carbon-rich residue, known as biochar, enhances soil structure, water-holding capacity, cation-exchange capacity, and nutrient retention, and is widely promoted for carbon sequestration.
· Pyrolysis of organic material does not directly produce synthetic biofuel — Correct. Pyrolysis yields a raw bio-oil (pyrolysis oil) that is acidic, unstable, and viscous; it must undergo further upgrading (hydrotreating, catalytic cracking) before becoming a usable synthetic biofuel, so it is not produced directly in finished form.