In the determination of melting range of a compound, suppose compound R melts at
ID: 1063963 • Letter: I
Question
In the determination of melting range of a compound, suppose compound R melts at 175 degree C and compound S melts at 190 degree C. If a mixture X contains mostly R with small amounts of S, then which of the following statement is true? X always melts below 175 degree X melts between 175 degree C and 190 degree C X melts higher than 190 degree C melting point cannot be determined as one need to know the relative amount of Q to P. melting point of X cannot be determined unless one knows the exact structure of P Q. In determining the melting point the phenylhydrazone derivative, what happens when the rate of heating is 20 degree C per minute? the compound would sun to decompose faster the melting point range would be larger than it actually should be no effect What is the primary purpose of a research lab notebook? to write down what one expects to be the outcome of the experiment to record down procedures and observations such that only the author can understand and reproduce the experiment to copy down the corrected procedures and observations from a scratch paper which was used previously to write down the results and observations to immediately record down actual experimental procedures used and the resulting observations and outcomes so that anybody else reading the notebook would be able to understand what was done Given the reaction A + B rightarrow 2 C + D Suppose Molecular Weight of A is 50. B is 100, C is 60. Suppose one reacted one gram of A with one gram of B. and got 0.12 grams of C. What is the yield in this reaction? Write your answer at the back of Scantron on question 63. An ideal solution containing 70 mi compound A (b, p. = 102 degree C) and 30 ml toluene (b.p. = 11l degree C) can be separated using simple fractional spinning band) distillation.) Assuming a very efficient distillation column is used, at the end of the distillation, the distilland in #1 will be composed of pure A pure toluene 30% toluene none of the above) Suppose the temperature-composition diagram of A and B is as shown below. Using an extremely efficient distillation column, the distillate in the a 50:50 mixture of A and B will be composed of: pare A pure B 40% A and 60% B 60% A and 40% B none of the above Which of the four compounds below will have second highest GC retention time? Pentanol butanol 3-methylbutanol 2-methylpropanol)Explanation / Answer
28. Answer:- A
X is impure solution of R having S as impurities. Presence of impurities always lower melting point. So solution of R having S as impurities would melt below its melting point i.e 175°C