A single mixture containing only CHCl3 and CH2Cl2 was divided into five parts to obtain sa...

A single mixture containing only CHCl3 and CH2Cl2 was divided into five parts to obtain samples for replicate determinations. Each sample was dissolved in methanol and electrolyzed in a cell containing a mercury cathode. The potential of the cathode was held constant at -1.80 V (versus SCE). Both compounds were reduced to CH4 (see Problem for the reaction). Calculate the mean value of the percentages of CHCl3 and CH2Cl2 in the mixture. Find the standard deviations and the relative standard deviations.

Problem At a potential of -1.0 V (versus SCE), CCl4 in I иЦ methanol is reduced to

Several different 0.750-g samples containing CCl4, CHG3, and inert organic species were dissolved in methanol and electrolyzed at - 1.0 V until the current approached zero. A coulometer indicated the charge required to complete the reaction as given in the middle column of the table below. The potential of the cathode was then adjusted to — 1.8 V. The additional charge given in the last column of the table was required at this potential.

Calculate the percentage of CCL. and CHO3 in each mixture.