Question

Which compound is formed when calcium carbide reacts with heavy water? (a) \(\mathrm{C}_{2} \mathrm{D}_{2}\) (b) \(\mathrm{CaD}_{2}\) (c) \(\mathrm{CD}_{2}\) (d) \(\mathrm{Ca}_{2} \mathrm{D}_{2}\)

Short answer

The compound formed when calcium carbide reacts with heavy water is \(\mathrm{C}_{2}\mathrm{D}_{2}\).

Step-by-step solution

Write down the reaction

First, write down the chemical reaction of calcium carbide with water. The general reaction of calcium carbide (CaC2) with water (H2O) is: CaC2 + 2H2O -> C2H2 + Ca(OH)2Replacing H2O with heavy water (D2O), gives us the reaction:CaC2 + 2D2O -> C2D2 + Ca(OD)2

Identify the product formed

From the adapted reaction with heavy water, we can see that the compound formed is C2D2, which is deuterated ethyne (acetylene), and deuterated calcium hydroxide Ca(OD)2 as a by-product. Therefore, the compound of interest from the given options is C2D2.

Key concepts

Chemical reactions

A chemical reaction is a process in which one or more substances, called reactants, are converted into one or more new substances, known as products. These transformations involve rearragement of atoms and changes in chemical bonds.

For instance, in the reaction between calcium carbide (CaC₂) and heavy water (D₂O), a chemical reaction takes place where the carbide reacts with heavy water to form a deuterated compound and a deuterated by-product, showcasing a change in chemical composition. The carbide's carbon atoms bond with the deuterium atoms from the heavy water, which results in the formation of deuterated acetylene (C₂D₂) and deuterated calcium hydroxide (Ca(OD)₂).

Understanding the basic principles of chemical reactions, such as those involving substitution of elements like deuterium for hydrogen, can greatly aid in predicting the outcomes of such interactions.

Deuterated compounds

Deuterated compounds are a variant of chemical compounds in which the hydrogen atoms (H) are replaced by deuterium (D), a stable isotope of hydrogen with an additional neutron. This replacement can affect the physical and chemical properties of the compound due to the mass difference between hydrogen and deuterium.

In our example, when calcium carbide reacts with heavy water, a deuterated compound, specifically deuterated acetylene (C₂D₂), is formed. Deuterated compounds are valuable in various research applications due to their distinctive properties and also play a crucial role in nuclear magnetic resonance (NMR) spectroscopy as they can help in reducing background noise and increasing the accuracy of the measurements.

Understanding how deuterium behaves in chemical reactions compared to hydrogen can deepen the insight into isotopic effects in chemistry and provide a foundation for interpreting reactions involving heavy water.

Stoichiometry

Stoichiometry is the area of chemistry that pertains to the quantitative relationships between the reactants and products in a chemical reaction. It is based on the conservation of mass principle, which states that matter cannot be destroyed or created in a chemical reaction.

For the chemical reaction involving calcium carbide and heavy water, stoichiometry allows us to understand the proportions of reactants required and the amount of products formed. The balanced equation CaC₂ + 2D₂O -> C₂D₂ + Ca(OD)₂ indicates that one mole of calcium carbide reacts with two moles of heavy water to produce one mole of deuterated ethyne and one mole of deuterated calcium hydroxide. Using stoichiometry, not only can we predict the products of a reaction, but we can also calculate the amounts needed and yielded, which is fundamental for practical applications in fields like chemistry and engineering.