Question

Propyne is produced during the hydrolysis of:
A. $Ca{C_2}$
B. $A{l_4}{C_3}$
C. $M{g_2}{C_3}$
D. $SiC$

Answer 1

Hint: We know that propyne is an alkyne. It has a triple bond in it. The molecular formula of propyne is ${C_3}{H_4}$. The molecular weight of propyne is $40$.In the process of hydrolysis we react the compound with water to obtain products. $Ca{C_2}$ is known as calcium carbide. $A{l_4}{C_3}$ is known as aluminium carbide. $M{g_2}{C_3}$ is known as magnesium carbide and $SiC$ is known as silicon carbide.

Complete step by step solution:
In the question it is given that after hydrolysis the product obtained is propyne. So, we will check the options one by one to find the correct answer. When $Ca{C_2}$ undergoes a hydrolysis reaction the product we will get is acetylene. The hydrolysis reaction of $A{l_4}{C_3}$ can be written as $A{l_4}{C_3} + 12{H_2}O \to 3C{H_4} + 4Al{(OH)_3}$. We can see that the organic compound we obtained is methane. Aluminium hydroxide is also produced in this reaction which is amphoteric in nature. Aluminium hydroxide is a weak base.
 The hydrolysis reaction of $M{g_2}{C_3}$ can be written as $M{g_2}{C_3} + {H_2}O \to 2Mg{(OH)_2} + {C_3}{H_4}$. We can see that propyne is being produced in this reaction. Magnesium hydroxide is also produced in this reaction which is a strong base.
Hydrolysis of $SiC$ gives methane as the product.
So, from the above explanation and discussion it is clear to us that propyne is produced in the hydrolysis reaction of $M{g_2}{C_3}$.

Hence, the correct answer of the given question is option: C. $M{g_2}{C_3}$.

Note:
Always remember that the hydrolysis reaction of magnesium carbide produces magnesium hydroxide and propyne. Magnesium hydroxide is a strong base. Remember the chemical equations $A{l_4}{C_3} + 12{H_2}O \to 3C{H_4} + 4Al{(OH)_3}$ and $M{g_2}{C_3} + {H_2}O \to 2Mg{(OH)_2} + {C_3}{H_4}$,as they are very important reactions. The hydrolysis of aluminium carbide and silicon carbide produces methane as the product.