If the crucible wasn't covered with a lid the reactants may have produced a gas that was released into the surroundings, or mass may have been lost in the form of water vapour.
The hydrocarbon is used in excess.
<h3><u>Explanation</u>:</h3>
The bromination of an arene is not simple as bromination of an alkane. This is because the carbocation or free radicle formation in benzene is a very energy consuming process. This is why a lewis base like aluminium bromide or ferric bromide is used. The ferric bromide takes in the bromine radicle and forms the brominium cation which helps in the formation of electrophile. Now this electrophile brominium cation attacks the benzene ring and forms a temporary sp3 hybrid carbon intermediate. Then the hydrogen is taken by the FeBr4- forming HBr and regenerating the FeBr3 as well as Aromaticity of the arene species at the same time. Here hydrocarbon is used in excess just to prevent the chances of multiple substitution in the same arene molecule.
Answer:
Chemical reaction are irreversible. Some of the example of chemical reaction are cooking, rusting, and burning. During a chemical reaction, the composition of substances changes and the particles rearrange to form a new substance. The new substance formed after chemical reaction of substance has different physical and chemical properties.
When a chemical reaction occur, the atoms or molecules of the substances change its physical and chemical properties such as while cooking of vegetable, the molecules of vegetable undergo changes in their properties and form a new substance which is different from the earlier.
The element in the periodic table with the provided electron configuration is Chlorine. Cl it is found as in element in Group 7 of the periodic table.
