Question

Criteria for purity of organic solid is

Answer 1

Melting point

Is considered to be the best criteria for purity of a substance. The purified sample is mixed with a small quantity of pure compound and melting point of mixture is determined.

Answer 2

Dear Student,

◆ Pure substance -

• Pure solid is a solid having constant chemical composition and characteristic properties.
• They are formed by single type of atom/molecule/compound.
• For example, table salt, pure metal, etc.

# Criteria for purity of solids -

• Melting point is used as criteria for purity of solids.
• Pure solids will have sharp and fixed melting point. For example, pure NaCl always melts at 801 ℃.
• Impure solids have lower and variable melting point due to presence of impurity. For example, adulterated NaCl will have variable low melting point.

* Some also use density of solids as criteria for purity.

Thanks dear...