Question

What are \(X\) and \(Y\) respectively in the following reactions?
\[ X+D_2O\rightarrow C_2D_2+P \] \[ Y+D_2O\rightarrow CD_4+Q \]

• A. \(\mathrm{AlCl_3,\ CaCl_2}\)
• B. \(\mathrm{Be_2C,\ Al_4C_3}\)
• C. \(\mathrm{Al_4C_3,\ CaC_2}\)
• D. \(\mathrm{CaC_2,\ Al_4C_3}\)

Hint:

\(\mathrm{CaC_2}\) gives acetylene, while \(\mathrm{Al_4C_3}\) gives methane on reaction with water or heavy water.

Answer 1

The Correct Option is D

Step 1: Read what each product tells us.
$X$ reacts with heavy water to give deuterated acetylene $C_2D_2$, and $Y$ reacts with heavy water to give deuterated methane $CD_4$. The carbide identity is fixed by which hydrocarbon forms.
Step 2: Match acetylene to its carbide.
A carbide that releases a two carbon $C_2$ unit on hydrolysis is calcium carbide, $CaC_2$, an acetylide.
Step 3: Write the reaction for $X$.
$\mathrm{CaC_2 + 2D_2O \rightarrow C_2D_2 + Ca(OD)_2}$, confirming $X = CaC_2$.
Step 4: Match methane to its carbide.
A carbide that releases single carbon $CH_4$ (here $CD_4$) units on hydrolysis is aluminium carbide, $Al_4C_3$, a methanide.
Step 5: Write the reaction for $Y$.
$\mathrm{Al_4C_3 + 12D_2O \rightarrow 3CD_4 + 4Al(OD)_3}$, confirming $Y = Al_4C_3$.
Step 6: Choose the option.
So $X = CaC_2$ and $Y = Al_4C_3$, which is option (4). \[ \boxed{X = \mathrm{CaC_2},\ Y = \mathrm{Al_4C_3}} \]