The fuel with the highest cetane number is: MCQ with Answer and Explanation

Explanation:
Methanol (wood alcohol) is highly toxic. When ingested, it is metabolized by the enzyme alcohol dehydrogenase into formaldehyde and then formic acid. Formic acid interferes with mitochondrial function, leading to metabolic acidosis, optic nerve damage, and blindness. Both statements are correct and R explains A.

Explanation:
The mass of an atom is almost entirely concentrated in its tiny central nucleus. This is because the nucleus contains protons and neutrons, which are much heavier than the extranuclear electrons. Since electrons have negligible mass, R correctly explains why the mass is localized in the nucleus.

Explanation:
In AlCl₃, aluminium combines with three chlorine atoms. Chlorine has a valency of 1 (needs one electron to complete its octet). By the criss-cross method, Al has valency 3 because it loses three electrons to achieve a stable octet (Al³⁺). Thus, the formula is AlCl₃. Aluminium's electronic configuration is 2,8,3, so it loses three valence electrons. Exam tip: Valency equals the number of electrons lost, gained, or shared to complete octet.