Question

Treatment of calcium carbide with water gives:
A: Ethene
B: Ethyne
C: Ethane
D: Benzene

Answer 1

Hint: Calcium carbide is also known as calcium acetylide. The chemical formula of calcium carbide is $Ca{C_2}$. Pure calcium carbide is a colorless solid but pieces of technical-grade calcium carbide are grey or brown.

Complete answer:Calcium carbide $\left( {Ca{C_2}} \right)$ reacts with water and moisture to produce acetylene gas and lime. Acetylene is flammable due to which it may catch fire with the heat evolved in reaction. IUPAC name of acetylene is ethyne. The reaction involved is written below:
$Ca{C_2} + {H_2}O\xrightarrow{{}}Ca{\left( {OH} \right)_2} + {C_2}{H_2}$
$Ca{C_2}$ is calcium carbide
${H_2}O$ is water
$Ca{\left( {OH} \right)_2}$ Is calcium hydroxide
${C_2}{H_2}$ Is ethyne
So, the correct answer is option B that is ethyne.

Additional information:
Ethyne is an unsaturated hydrocarbon. The common name of ethyne is acetylene. Hydrocarbons in which there is a single bond between carbon atoms such hydrocarbons are called saturated hydrocarbons on the other hand hydrocarbons in which there is a double or triple bond between carbon atoms are called unsaturated hydrocarbons. Acetylene is the simplest alkyne. Acetylene gas is widely used as a fuel. In pure form, it is unstable so it is handled as a solution. Pure acetylene is odorless but commercial grades usually have a marked odor due to impurities. It is mainly manufactured by partial combustion of methane$\left( {C{H_4}} \right)$. Acetylene is not toxic but when generated from calcium carbide it can contain toxic impurities such as traces of phosphine and arsine.


Note:
Suffix ane is used for hydrocarbons in which there is a single bond between carbon and carbon. Similarly, the suffix ene is used for hydrocarbons in which there is a double bond between carbon and carbon, and the suffix -yne is used for hydrocarbons in which there is a triple bond between carbon and carbon.