Sahil took a white solid from his teacher to find out its melting point. During the experiment, he found that the melting point was 148° . But, the teacher told him that actual melting point of the solid is 150°  . What could be the reason for Sahil’s observation ?

Melting point of a solid depends upon the procedure and the amount taken

Solids can have different melting points depending upon the method of storage

The solid contains some impurities mixed with the pure compound

If solid is heated strongly, the melting point increases