Question

The diagram below shows the melting and boiling points of four different substances. Which substance has a melting point at ${-20}^{\circ }C$? Arrange the four substances in ascending order of their melting and boiling points.

Answer 1

Substance	Melting point ${(}^{o}C)$	Boiling point ${(}^{o}C)$
A	$0$	$100$
B	$-60$	$160$
C	$-20$	$120$
D	$20$	$80$

From the table, the substance C has melting point at $-{20}^{o}C$.

Ascending order of melting points : $B<C<A<D$

Ascending order of boiling points : $D<A<C<B$