Nitric acid AsO, SbO, and TiO respectively. Some precious metals, such as pure gold and platinum-group metals do not react with nitric acid, though pure gold does react with "aqua regia", a mixture of concentrated nitric acid and hydrochloric acid. However, some less noble metals (Ag, Cu, ...) present in some gold alloys relatively poor in gold such as colored gold can be easily oxidized and dissolved by nitric acid, leading to colour changes of the gold-alloy surface. Nitric acid is used as a cheap means in jewelry shops to quickly spot low-gold alloys (< 14 carats) and to rapidly assess the
Nervonic acid Recent studies show that cord nervonic acid levels were lower in women with preeclampsia delivering male babies as compared to normotensive control group. But this does not happen with girl babies. These results suggest that male babies born to mothers with preeclampsia may be at an increased risk of developing neurodevelopmental disorders as compared to female babies. This acid is present in the composition of aged eye lens, but it does not appear in normal eye lens. This data shows that we can use the presence of nervonic acid (together with heneicosylic acid and docosahexaenoic acid) as biomarkers of aging