Question

Which among the given options is likely to be a pure substance?

• A. A colourless liquid that boils over the range $80-{90}^{\circ }\text{C}$
• B. A green solid which starts to melt at ${80}^{\circ }\text{C}$ and is completely melted at ${90}^{\circ }\text{C}$.
• C. A liquid that boils only at ${100}^{\circ }\text{C}$.
• D. Stainless steel.

Answer 1

The correct option is C A liquid that boils only at ${100}^{\circ }\text{C}$.

a) The liquid does not have a fixed boiling point.Hence is not a pure substance.
b) The solid continues to melt with the increase of temperature. Hence, it is not a pure substance.
c) The liquid has a fixed boiling point. Hence, it is a pure substance.
d) Stainless steel is an alloy. It is a homogeneous mixture. Hence, it is not a pure substance.