Question

The curves below represent the variation of temperature with time when pure and impure samples of a solid were heated separately.

1. Which curve shows the variation in temperature for the pure solid? Explain. 
2. State the effect of impurities on the melting and boiling points of a pure substance.
   • Melting points 
   • Boilling points 

Answer 1

1. Sharp/ constant melting point and boiling point.
2.   
   • Melting points  - lower the M.P 
   • Boilling points  - raises the b.p