Chemistry

In 2012, the Czech Republic was paralyzed by „The methanol affair“. Some manufacturers of alcoholic drinks at black market, to avoid of paying the high consumption tax, added methanol into the alcoholic drinks instead of ethanol due to similarity in taste and smell. By this method, they prepared alcoholic beverages significantly cheaper. Unfortunately, the methanol is highly toxic compound. Their ignorance of chemistry and toxicology knowledge, however, was fatal.

Charles and Michael, they often go to restaurant to have a drink. Once, they had a sweet peppermint liqueur, which has a typical green color. Suddenly, Michel, looking at the liqueur, got angry, saying: “that is terrible, everywhere are substitutes. I bet that this liqueur, this is the same case. Look at the color. It must be something poisonous inside. Surely, there is more dye inside than allowed. And, it is killing us slowly. We should take some legal action against manufacturer of this killing drink, should not we?

Mr. Black is owner of a small pharmacy shop. He sells a lot of pharmacy products. In his portfolio, there is also a hydrogen peroxide solution sold as a disinfection. Sold solution should be of 3 % w/w. Nevertheless, Mr. Black is not sure, whether his supplier does not cheat and to earn more, he sells him hydrogen peroxide solution with much smaller concentration.

Can you help to Mr. Black and find the concentration of hydrogen peroxide solution from his pharmacy shop? Is the solution sold in his shop OK?

The wine is a product that consists of several components, most of which is water (91 %). Besides water, ethanol (9-14 %), residual sugar, dyes and tannins, there are present also acids. There are more acids, but the most represented is tartaric acid, then malic, citric and lactic acid.  The proportion of the acids’ amount is a reason of characteristic taste and bitterness of each wine. Low content of acid results in insipid taste of wine, so the determination of total acidity is an important controlled item.

The company producing certain alcoholic beverage is suspect that they use very cheap, but non legal, dye to color their product. Unfortunately, the non-legal dye can cause, in some cases, health problems and allergic reactions. To protect costumer rights, it is necessary to analyze the beverage and identify the used dyes. On the basis of your analysis, the steps to set the right will be applied and the guilty party will be penalized (if the law is broken).