Question

(a) Write a balanced equation for the preparation of \(\mathrm{NaN}_{3}\) from \(\mathrm{NaNH}_{2}\) with \(\mathrm{NaNO}_{3}\) (b) Suggest a route for preparing the precursor \(\mathrm{NaNH}_{2}\) (c) How might NaN react with \(\mathrm{Pb}\left(\mathrm{NO}_{3}\right)_{2}\) in aqueous solution?

Short answer

a) \(3 \mathrm{NaNH}_2 + \mathrm{NaNO}_3 \rightarrow \mathrm{3 NaN_3} + \mathrm{NaOH} + 3 \mathrm{H}_2\) b) Prepare \(\mathrm{NaNH}_2\) from \(\mathrm{Na} + \mathrm{NH}_3\). c) \(\mathrm{NaN_3}\) decomposes in presence of \(\mathrm{Pb(NO_3)_2}\).

Step-by-step solution

Write the Reaction Equation

To write the reaction equation for the preparation of \(\mathrm{NaN}_{3}\) from \(\mathrm{NaNH}_{2}\) and \(\mathrm{NaNO}_{3}\), you need to identify the products and ensure the equation is balanced. Decompose \(\mathrm{NaNH}_{2}\) to produce \(\mathrm{NaN}_{3}\) and another compound, usually nitrogen gas as a by-product, while \(\mathrm{NaNO}_{3}\) could help in situ providing another reactant to stabilize the azide structure as represented below:\[3 \mathrm{NaNH}_2 + \mathrm{NaNO}_3 \rightarrow \mathrm{3 NaN_3} + \mathrm{NaOH} + 3 \mathrm{H}_2\]

Key concepts

Balancing Chemical Equations

Balancing chemical equations is a fundamental skill in chemistry that ensures the same number of each type of atom on both sides of the equation. This is due to the law of conservation of mass, which states that matter cannot be created or destroyed. When balancing equations, we need to adjust coefficients—the numbers placed before compounds—to achieve this balance.
To tackle the problem of balancing the equation for the preparation of \(\mathrm{NaN}_3\) from \(\mathrm{NaNH}_2\) and \(\mathrm{NaNO}_3\), we start by writing an unbalanced equation. We initially have \(\mathrm{NaNH}_2\) and \(\mathrm{NaNO}_3\) as reactants. The products in this case are \(\mathrm{NaN}_3\), \(\mathrm{NaOH}\), and hydrogen gas \(\mathrm{H}_2\).

• Start by listing the number of sodium (Na), nitrogen (N), hydrogen (H), and oxygen (O) atoms on both sides of the equation.
• Adjust coefficients to achieve the same number of each type of atom on both sides.
• In this specific reaction, the balanced equation becomes: \[3 \mathrm{NaNH}_2 + \mathrm{NaNO}_3 \rightarrow \mathrm{3 NaN}_3 + \mathrm{NaOH} + 3 \mathrm{H}_2\]

This equation shows that each reactant and product was used or produced in the right amounts to keep matter conserved.

Azide Compound Preparation

Azide compounds, like \(\mathrm{NaN}_3\), are fascinating due to their use in various applications, including airbags in automobiles because of their explosive decomposition to produce nitrogen gas.
Preparation of \(\mathrm{NaN}_3\) typically involves a chemical reaction where \(\mathrm{NaNH}_2\) (sodium amide) and \(\mathrm{NaNO}_3\) (sodium nitrate) react to form sodium azide. The compound \(\mathrm{NaNH}_2\) acts as a primary source of nitrogen, while the \(\mathrm{NaNO}_3\) lends some stability and aids in forming the azide group \(\mathrm{N}_3\).

• The balanced reaction from earlier provides a clear pathway for the synthesis. This involves careful handling and precise measurements to ensure product yield and safety.
• Sodium azide’s preparation is a classic example of transforming basic inorganic reagents into a more complex and useful compound.

Understanding the stoichiometry and reactivity of these compounds is crucial for synthesizing azides efficiently.

Inorganic Synthesis Routes

Inorganic synthesis is an excellent field that not only focuses on creating interesting and useful compounds but also includes understanding their pathways and transformations. Each synthetic procedure is designed based on the type of compounds and desired end products.
The preparation of \(\mathrm{NaNH}_2\), a precursor for \(\mathrm{NaN}_3\), represents a thoughtful step in the synthesis route. \(\mathrm{NaNH}_2\) can be prepared by passing ammonia gas over heated sodium, allowing it to directly react and form sodium amide.

• This specific route features simplicity and direct formation, which are critical in industrial applications for efficiency and cost-effectiveness.
• Moreover, when considering reactions such as the one between \(\mathrm{Pb(NO}_3)_2\) and \(\mathrm{NaN}_3\), predicting interactions and possible products yields a practical perspective on synthesis outcomes.
• The aqueous reaction mentioned likely results in lead azide \(\mathrm{Pb(N}_3)_2\) formation along with other by-products, emphasizing the need for meticulous planning in inorganic preparation.

This area explores the chemical transformations, emphasizing inventiveness, safety protocols, and understanding the role of catalysts and reactants in synthesis.