Problem 110 - A Complete Resource Book in Chemistry for JEE Main

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

Step-by-Step Solution

Answer

Option (d) 1 and 3 are correct.

Step 1: Understanding the Reaction of SnCl2 with Na2CO3

Stannous chloride, or SnCl₂, does not directly produce SnO when boiled with Na₂CO₃. Instead, SnO is formed as a byproduct. In this reaction, either tin hydroxide or tin carbonate is initially formed, which then dehydrates to produce tin (II) oxide, SnO.

Step 2: Analyzing the Heating of Tin Hydroxide

When tin hydroxide is heated in air, it typically forms SnO₂ instead of SnO because the presence of oxygen in the air facilitates complete oxidation. Therefore, heating tin hydroxide in air does not directly yield SnO.

Step 3: Examining the Heating of Tin Oxalate

Heating tin oxalate (\(\mathrm{SnC}_{2} \mathrm{O}_{4}\))in absence of air results in decomposition. During this process, tin oxalate decomposes to form SnO along with the release of carbon dioxide and carbon monoxide.

Step 4: Conclusion Based on Analysis

Based on the analysis, methods (1) and (3) can successfully yield SnO. Method (2) results in SnO₂ production due to the presence of air. Therefore, "1 and 3" are the correct methods for producing SnO.

Key Concepts

Tin Compounds

Tin compounds are chemical compounds that contain the element tin, which is represented by the symbol Sn on the periodic table. These compounds play significant roles in various industrial processes and applications:

• **Stannous Compounds:** Also known as tin(II) compounds, these are tin in the +2 oxidation state. Stannous chloride (SnCl₂) is a common example used in electroplating and as a reducing agent.
• **Stannic Compounds:** Tin(IV) compounds, where tin is in the +4 oxidation state, include stannic oxide (SnO₂) and stannic chloride (SnCl₄), used in ceramics and glass production.

Understanding tin compounds helps in comprehending their chemical behavior and industrial applications. Tin is a versatile element forming stable compounds with different oxidation states, thereby broadening its usability in various fields.

Stannous Chloride Reactions

Stannous chloride (SnCl₂) is a versatile compound that reacts with other substances to produce tin oxides or other derivatives. It's particularly notable for its reactions with bases like sodium carbonate ( SnCl₂ + Na₂CO₃ ):

• **Reaction with Sodium Carbonate:** When SnCl₂ is mixed with Na₂CO₃, stannous carbonate or tin hydroxide may form. Both intermediates can then dehydrate to produce tin(II) oxide (SnO).
• **Reduction Properties:** SnCl₂ is a strong reducing agent, often used to convert metal ions to a lower oxidation state in solutions.

These reactions highlight the importance of careful control of reaction conditions, such as temperature, to favor the production of desired tin compounds, like SnO, from their intermediates.

Tin Oxide Preparation

Tin oxide, specifically tin(II) oxide ( SnO ), can be prepared using different methods, emphasizing the variability in chemical synthesis:

• **Boiling SnCl₂ with Na₂CO₃:** In this process, either tin hydroxide or tin carbonate forms as an intermediate. These then dehydrate to yield SnO.
• **Heating Tin Hydroxide in Air:** Although this method leads to oxidation due to the presence of air, forming SnO₂ rather than SnO, controlling the environment can modify outcomes.
• **Heating Tin Oxalate:** When SnC₂O₄ is heated in the absence of air, it decomposes into SnO, along with the release of carbon monoxide and carbon dioxide.

Understanding these preparation pathways is crucial for optimizing conditions to obtain specific tin oxide forms, which have different applications based on their oxidation states and chemical properties.