Problem 3 - Chemistry in 30 days

Question

Butter of tin is (a) \(\mathrm{SnCl}_{2} \cdot 5 \mathrm{H}_{2} \mathrm{O}\) (b) \(\mathrm{SnCl}_{2}-2 \mathrm{H}_{2} \mathrm{O}\) (c) \(\mathrm{SnCl}_{4}+4 \mathrm{H}_{2} \mathrm{O}\) (d) \(\mathrm{SnCl}_{4}+5 \mathrm{H}_{2} \mathrm{O}\)

Step-by-Step Solution

Answer

The 'butter of tin' is SnCl_2  5H_2O, option (a).

Step 1: Identify Properties

The term 'butter of tin' refers to a specific chemical compound of tin, commonly known for its hydrated form. Tin compounds often include tin(II) chloride or tin(IV) chloride with water molecules.

Step 2: Understanding Tin Compounds

Tin(II) chloride (SnCl_2) is commonly found in hydrated forms. Two well-known hydrates are SnCl_2  5H_2O and SnCl_2-2H_2O, with 5H_2O formations often labeled as butter of tin due to its buttery consistency.

Step 3: Analyze Answer Options

Convert each given option into its chemical name or common identity. Option (a) is tin(II) chloride pentahydrate, option (b) is tin(II) chloride dihydrate, option (c) is tin(IV) chloride with water but not a hydrate, and option (d) is also not a common hydrate.

Step 4: Determine the Correct Compound

Based on common names and hydrated structures, 'butter of tin' is identified as SnCl_2  5H_2O. This corresponds to option (a), which is tin(II) chloride pentahydrate.

Key Concepts

Tin Compounds

Tin is a versatile metal that forms various chemical compounds, which can have different chemical properties and uses. The primary types of tin compounds are tin(II) and tin(IV) compounds, known as stannous and stannic compounds respectively. These compounds are often used in industrial applications due to their reactive characteristics.

Tin(II) compounds include tin(II) chloride (SnCl_2), which is employed in the plating processes and as a reducing agent in organic synthesis. On the other hand, tin(IV) compounds, like tin(IV) chloride (SnCl_4), are used as catalysts in the production of plastics and silicones.

• Tin(II) compounds generally react with oxygen to form compounds like tin(II) oxide.
• Tin(IV) compounds display tetrahedral geometry due to their oxidation state.

Understanding the different tin compounds helps in selecting the right chemical for specific industrial applications.

Hydrated Tin Chloride

Hydrated tin chloride refers to tin chloride that incorporates water molecules in its crystalline structure. These hydrates are fascinating due to their diverse chemical and physical characteristics.

Tin(II) chloride, for instance, can form hydrates like tin(II) chloride dihydrate (SnCl_2·2H_2O) and tin(II) chloride pentahydrate (SnCl_2·5H_2O). The latter, due to its buttery texture, is often referred to as ‘butter of tin’. These hydrates are crucial in understanding different hydration levels and stability.

• SnCl_2·5H_2O is commonly used in electroplating as it ensures smooth deposition and high-quality finishes.
• Hydrates can influence the solubility and reactivity of a compound, essential for both synthesis and industrial optimization.

Recognizing the important properties of these compounds is key to their practical applications.

Chemical Nomenclature

Chemical nomenclature is a systematic method of naming chemical compounds. This terminology is essential for clear communication in the scientific community, ensuring everyone understands precisely which compound is being discussed.

For instance, tin(II) chloride pentahydrate is the chemical name for (SnCl_2·5H_2O), where "pentahydrate" indicates the presence of five water molecules. Each part of the name provides information about the molecular composition and structure.

• "Tin(II)" signifies the oxidation state of the tin atom, which is +2 in this scenario.
• The suffix "hydrate" indicates water molecules within the crystalline structure.

By learning the nomenclature structure, students can decode complex chemical formulas easily and predict compound properties such as solubility and stability.