ooredo 11:35 AM 2 mybb.qu.edu.qa 1. In an experiment, an isolated unknown compou
ID: 546117 • Letter: O
Question
ooredo 11:35 AM 2 mybb.qu.edu.qa 1. In an experiment, an isolated unknown compound showed an observed melting range of 120-124 °C. Which is more likely to be, compound X (listed mp 127-128 °C) or Y (listed mp 116-117 °C)? Discuss your answer.(1 point 2. An unknown white solid has melting point range 119-121° C Benzoic acid is a white solid of 122 C melting point. How can a student confirm the identity of the unknown solid (is is the benzoic acid or not) ( point) 3. An unidentified compound is observed to melt at 11 °C with the evolution of a gas. The sample then solidifies and does not melt until the temperature reaches 155 °C, at which time it again melts sharply. Briefly explain these observations. (1 point) 4. What is the effect of a small amount of impurity on both the melting point and the boilg point of organic compounds. Explain why? (2 point) 5. The melting point of a pure compound is a unique property of that compound, independent of its source. Is this statement true or false? (1 point)Explanation / Answer
Ans 1
The tendency of melting points is always to be lowered.
Nothing can raise a melting point.
the compounds with the higher melting point used in this experiment
It is more likely to be compound X which has higher melting point range than Y.
Alternative-
compound Y is an impure sample which has the melting point range less than 116-117 °C, therefore any compound that melts at 120-124 °C cannot be Y and could be X.
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