Practice MCQ Questions and answers on Chemistry-GK

Copper was first used by man over 10,000 years ago. A copper pendant discovered in what is now northern Iraq has been dated about 8700 B.C. For nearly five millennia copper was the only metal known to man, and thus had all the metal applications.

In chemistry, hydronium is the common name for the aqueous cation H 3O+ , the type of oxonium ion produced by protonation of water.

Cesium(Cs) is the most electropositive element.

Permanent hardness of water cannot be removed by simple physical methods like boiling, filtering and distillation.

0.01 minute is the most dangerous to handle.

Ethylene gas, acetylene gas liberated from calcium carbide, and ethephon are some of the commercial ripening agents used successfully in the trade and they have been widely studied for their effectiveness on initiating and accelerating the ripening process and their effect on fruit quality and health related issues. Green fruits are ripened by ethylene gas.

Zone refining is a very useful method to get metals with very high purity such as silicon and germanium. It is also referred to as zone melting, floating zone process, and travelling melting zone.

The main chemical constituent of the oil of cardamom which is responsible for flavour of this oil is cineole.

HF has the highest percentage of ionic character because F has the greatest electronegativity. F, Cl, I, and Br are all in the same group so that means their electronegativity (and thus percentage of ionic character) decreases as they go down the group in the periodic table.

The high reactivity of fluorine is due to its high electronegativity.