Question

At what temperature does the ash is determined by heating to complete its combustion?

(a) 400^o C

(b) 600^o C

(c) 850^o C

(d) 750^o C

The question was asked during an interview.

My doubt stems from Coal topic in section Fuels and Combustion of Engineering Chemistry II

Answer 1

Correct option is (d) 750^o C

For explanation I would say: Precisely the determination of ash is done by heating it at 400^o C, until most of its carbonaceous matter is burnt off. Then is it heated at 750^o C for one hour so as to complete its combustion.