Answer:
benzamide
Explanation:
Compound melting Point ,ºC Melting Pont Mixture, ºC
X 131 - 133
trans-cinnamic 133 - 134 110 - 120
acid
benzamide 128 - 130 130-132
malic acid 131 -133 114 -124
Benzoin 135 - 137 108 - 116
The compound X is benzamide since the melting point range is the one closest to this compound ( 130-132 ºC)
The reason there is not an exact match is not due due to the presence of impurities. The presence of impurities always lower the melting point ( it is a coligative property such as the melting point depresion of salt and water )
The reason for the deviation must be be some other factors such as preparation of the sample in the capillary, errors in reading the thermometer, rate of heating, etc.
