Practice MCQ Questions and answers on Chemistry-GK

Fluorine is the most reactive halogen.

In 1869 Russian chemist Dimitri Mendeleev started the development of the periodic table, arranging chemical elements by atomic mass.

Concentrated Sulphuric acid can only be stored in glass, no metal lids, some plastic containers. It will attack anything organic, causing severe burns, the good thing is it will not start a fire but if it goes into contact with a metal it may generate hydrogen gas, an explosion risk.

Sulphur is a non-metal that shows allotropy in the liquid state. If sulphur is heated slowly the changes between the different forms can be observed. These changes are in the form of colour and viscosity (thickness) of the liquid. If the dark brown liquid sulphur is poured into a beaker of cold water, plastic sulphur is formed. This is an elastic, rubber-like form of sulphur.

Sulphuric acid is dibasic.

When conc. H2SO4 is added to dry KNO3, brown fumes are evolved. These fumes are due to NO₂.

An aliphatic compound is a hydrocarbon compound containing carbon and hydrogen joined together in straight chains, branched trains or non-aromatic rings. Waxes are a class of chemical compounds that are plastic (malleable) near ambient temperatures. Characteristically, they melt above 45 degree C (113 degree F) to give a low viscosity liquid. Waxes are insoluble in water but soluble in organic, non-polar solvents. All waxes are organic compounds, both synthetic and naturally occurring. Waxes are organic compounds that characteristically consist of long alkyl chains. Natural waxes are typically esters of fatty acids and long chain alcohols. Synthetic waxes are longchain hydrocarbons lacking functional groups. Waxes are biosynthesized by many plants and animals. They typically consist of several components, including wax esters, wax acids, wax alcohols, and hydrocarbons. Wax esters are typically derived from a variety of carboxylic acids and a variety of fatty alcohols.

Adding Cl₂ to benzene in the presence of AlCl₃ is an example of substitution reaction.

Benzene can not undergo elimination reaction.

Benzene, C₆H₆, is the simplest aromatic hydrocarbon and was recognized as the first aromatic hydrocarbon, with the nature of its bonding first being recognized by Kekulé in the 19th century. Each carbon atom in the hexagonal cycle has four electrons to share.