Application-based Questions
1. In the following set of substances, one item does not belong to the set. Select this item and
explain why it does not belong to the set:
Hydrogen, Oxygen, Steam, Chlorine
2. A mixture contains two components W and X. The component W is a white solid which
is soluble in water. It is obtained on a large scale from sea-water by the process Y. The
component X consists of tiny pieces called filings which can be attracted and removed from
the mixture by a device Z.
a. What do you think is component W?
b. Name the process Y.
Name the component X.
d. What could the device Z be?
Answers
Answer:
1) The most common compound of chlorine, sodium chloride (common salt), has been known since ancient times. Around 1630, chlorine gas was first synthesized in a chemical reaction, but not recognized as a fundamentally important substance. Characterization of chlorine gas was made in 1774 by Carl Wilhelm Scheele, who supposed it to be an oxide of a new element. In 1809, chemists suggested that the gas might be a pure element, and this was confirmed by Sir Humphry Davy in 1810, who named it from Ancient Greek"pale green". Nearly all chlorine in the Earth's crust occurs as chloride in various ionic compounds, including table salt. It is the second most abundant halogen and 21st most abundant chemical element in Earth's crust. Elemental chlorine is commercially produced frombrine by electrolysis. The high oxidizing potential of elemental chlorine led commercially to free chlorine's bleaching and disinfectant uses, as well as its many uses of an essential reagent in the chemical industry.
Answer:
1- chlorine, because everything is in gaseous form except chlorine.