Question

\(\mathrm{SnO}\) can be prepared by (1) boiling a stannous chloride solution with \(\mathrm{Na}_{2} \mathrm{CO}_{3}\) (2) heating tin hydroxide in air (3) heating tin oxalate \(\left(\mathrm{SnC}_{2} \mathrm{O}_{4}\right)\) in absence of air (a) 1 and 2 (b) 2 and 3 (c) 1,2 and 3 (d) 1 and 3

Short answer

(c) 1, 2, and 3

Step-by-step solution

Understanding the Reaction Possibilities

We need to determine which of the given reactions can produce \ \( \mathrm{SnO} \). The reactions involve different starting compounds of tin with specific processes.

Analyzing Reaction (1)

This reaction involves boiling a stannous chloride solution with \( \mathrm{Na}_{2} \mathrm{CO}_{3} \). This can facilitate the formation of \( \mathrm{SnCO}_{3} \) first, which upon decomposition produces \( \mathrm{SnO} \), given that \( \mathrm{CO}_{2} \) and \( \mathrm{O}_{2} \) are involved.

Analyzing Reaction (2)

Heating tin hydroxide in air (\( \mathrm{Sn(OH)}_2 \)) will cause it to dehydrate, releasing water, and forming \( \mathrm{SnO} \). This reaction proceeds as: \[ \mathrm{Sn(OH)}_2 \rightarrow \mathrm{SnO} + \mathrm{H}_{2}\mathrm{O} \].

Analyzing Reaction (3)

Heating tin oxalate \( \mathrm{SnC}_{2} \mathrm{O}_{4} \) in the absence of air will decompose it into \( \mathrm{SnO} \) and release gases like \( \mathrm{CO}_{2} \). The reaction is: \[ \mathrm{SnC}_{2} \mathrm{O}_{4} \rightarrow \mathrm{SnO} + 2 \mathrm{CO}_{2} \].

Concluding the Possible Combinations

Based on the analysis, \( \mathrm{SnO} \) can be produced by reactions (2) and (3). Reaction (1) also leads to \( \mathrm{SnO} \), therefore all reactions have the potential to form \( \mathrm{SnO} \). Thus, the answer is all three reactions together.

Key concepts

Stannous Chloride Reaction

In the preparation of Tin(II) oxide, or \( \mathrm{SnO} \), the reaction involving stannous chloride is quite interesting and integral. Stannous chloride, known chemically as \( \mathrm{SnCl}_2 \), can be reacted with sodium carbonate (\( \mathrm{Na}_2 \mathrm{CO}_3 \)) in a boiling solution to initiate a series of transformations. Initially, the reaction between stannous chloride and sodium carbonate leads to the formation of tin carbonate (\( \mathrm{SnCO}_3 \)). Tin carbonate is an unstable compound, especially when heated or boiled, and therefore it decomposes further. This decomposition is what leads to the production of tin(II) oxide. Though this reaction seems straightforward, it involves several intermediate steps:

• Formation of tin carbonate through the interaction of \( \mathrm{Na}_2 \mathrm{CO}_3 \) and \( \mathrm{SnCl}_2 \).
• Decomposition of tin carbonate upon heating to produce \( \mathrm{SnO} \).
• Release of gases such as \( \mathrm{CO}_2 \) during decomposition.

This method is quite efficient for \( \mathrm{SnO} \) preparation, as the boiling mechanism provides the necessary energy for the decomposition processes to occur.

Tin Hydroxide Decomposition

The decomposition of tin hydroxide is another method to prepare tin(II) oxide. Tin hydroxide, which is represented as \( \mathrm{Sn(OH)}_2 \), undergoes a dehydration reaction when heated in the presence of air. This type of reaction is called a thermal decomposition. When \( \mathrm{Sn(OH)}_2 \) is heated, it breaks down to form tin(II) oxide and water vapor is released. The simplified chemical equation for this decomposition reaction is as follows:\[ \mathrm{Sn(OH)}_2 \rightarrow \mathrm{SnO} + \mathrm{H}_2\mathrm{O} \]Important points about this reaction include:

• Enthalpy changes: Heating provides energy necessary for the removal of water from the hydroxide form.
• The water that is released is in gaseous form due to the elevated temperature.
• Air acts as an oxidizing environment although in this reaction, no further oxidation beyond \( \mathrm{SnO} \) occurs.

This approach to obtaining \( \mathrm{SnO} \) is quite straightforward and effective, particularly when controlled heating is used to facilitate the decomposition.

Tin Oxalate Decomposition

Finally, we have the method of tin oxalate decomposition to obtain \( \mathrm{SnO} \). Tin oxalate has the chemical formula \( \mathrm{SnC}_2 \mathrm{O}_4 \). When heated, especially in an environment without oxygen (absence of air), tin oxalate decomposes.During this process, tin oxalate breaks down and leads to the formation of tin(II) oxide. Additionally, the decomposition also leads to the release of carbon dioxide gas, which further confirms the reaction's progress:\[ \mathrm{SnC}_2 \mathrm{O}_4 \rightarrow \mathrm{SnO} + 2\mathrm{CO}_2 \]Key considerations in this reaction method include:

• The absence of air is crucial to avoid further oxidation of \( \mathrm{SnO} \) or interference in the desired decomposition pathway.
• Ensures a clean production of \( \mathrm{SnO} \) without impurities that could result from side reactions involving oxygen.
• The release of \( \mathrm{CO}_2 \) serves as an indicator that the decomposition is proceeding as intended.

Thus, heating tin oxalate is a valuable and relatively simple method to achieve \( \mathrm{SnO} \) production, especially when managed under controlled conditions.