A literature value for the melting point of acetanilide is 115 degree C. Why did

Question

A literature value for the melting point of acetanilide is 115 degree C. Why did a student find the melting point to be 112-114 degree C in a capillary tube? Indicate the best answer with an X. Literature values always differ from experimental values. An impurity present in the student sample. Equilibrium conditions cannot be attained in a capillary tube. Equilibrium conditions exist in the capillary tube. A student finds the melting point of a purified compound to be 112-114 degree C. What melting point should the student expect to find if a small amount of impurity were added to the compound? Indicate the best answer with an X. 112 degree C. 113 degree C. 113-114 degree C. 110-113 degree C. Two different compounds, Compound A and Compound B, both melt at 130 degree C. What melting point would be expected when equal amounts of A and B are mixed? Indicate the best answer with an X. 130 degree C. 130-131 degree C. 129 degree C. 128-129 degree C. A mixture that melts like a pure compound is called a _______ mixture. You have a compound you believe to be benzoic acid, an organic compound. Which of the following actions will best confirm or refute your hypothesis? Indicate the best answer with an X. Compare your mp with a literature value. Melt your compound and benzoic acid in separate capillary tubes at the same time and record the mp's. Conduct a mixed-melting point experiment. Melt your compound and benzoic acid in separate capillary tubes at different times and record the mp's. A solid should be packed firmly in a melting point tube because: Indicate the best answer with an X. holes in the sample cause it to melt too low. holes in the sample cause it to melt too high. packing keeps air out of the sample. all melting points will be taken in the same way.

Explanation / Answer

1) An impurity was present in the capillary tube

when there is an impurity present in capillary tube it reduces the melting point of a substance and capillary tube doesnot have anything to do with the melting point

2) 110 - 113 C

As presence of impurities will reduce the melting point from the actual melting point

3) 130 C

If two compounds have same melting point then melting point of mixture should be the same as that of either sample. If the two compounds are not identical, then the melting point will be depressed.

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