Which is the following statements is correct :
1- The use of paper for weighing is not acceptable practice for quantitative determination.
2- Cleaning solution is prepared from sodium dichromate and nitric acid.
3- Volumetric glassware shouldn’t be calibrated before use.
4- Chemical are placed directly on the balance pane.
5- The object to be weighing shouldn’t be at room temperature.

Liquid from a brewery fermentation contains 10% ethanol and 90% water. part of the fermentation product (50,000 kg/h) is pumped to a distillation column on the factory site. under current operating conditions, a distillate of 45% ethanol and 55% water is produced from the top of the column at a rate of one-tenth that of the feed. what is the composition of the waste "bottoms" from the still?