Chapter: Basic Concepts of Chemistry
Which one of the following is not a solution?
The concept of a solution is defined as a homogeneous mixture where one substance (solute) is completely dissolved in another (solvent). Common solutions include alloys, air, and emulsions like milk.
An alloy (e.g., brass = Cu + Zn), air (mixture of gases), and milk (emulsion of fat in water) are all recognized as solutions due to their uniform composition. In contrast, sugar (C12H22O11), when referenced as a solid state and not dissolved, forms a crystalline structure rather than a solution.
This distinction is prominent since:
Option A (Alloy): Mixture of metals. Option B (Milk): Emulsion of fat in water. Option C (Air): Gas mixture. Option D (Sugar): Compound, not a mixture.
Remember: "Solutions are mixtures, but solids like sugar stand alone!"
Diagram comparing solutions, compounds, and mixtures, highlighting the uniformity of solutions like alloys, air, and emulsions like milk versus distinct solids like sugar.
Verified against NCERT Class XI Chemistry, Chapter 2 (Structure of Atom and Chemical Bonding).
Kerosene and petrol mixture can be best separated by
Explanation: Kerosene and petrol mixture is separated by fractional distillation as kerosene and petrol has different boiling point.
Water gas is a mixture of:
Water gas, also known as synthesis gas, is produced via the reaction of hydrocarbons with steam. The primary reaction is:
Water gas is synthetically produced using methane (typically) and steam as illustrated above. It's crucial for industrial processes.
Remember "CO-HY" for Carbon Monoxide and Hydrogen–the components of water gas.
A flowchart showing the process of producing water gas from methane and steam, emphasizing the reaction conditions such as temperature and catalyst.
Verified against NCERT Class XII Chemistry, Chapter on Hydrocarbons.
Which among the following is the correct composition of Borax?
The chemical formula for Borax is represented as \( Na_2B_4O_7 \cdot 10H_2O \), encompassing the elements sodium, boron, oxygen, and hydrogen.
The complete composition is derived as follows:
Thus, Borax is a hydrated salt, and its use is common in several industrial applications, including glass making and as a cleaning agent.
Mnemonic: "Silly BOats Are Hopping" - represents Sodium (S), Boron (B), Oxygen (O), and Hydrogen (H) for Borax.
A comparative table illustrating the composition of Borax alongside similar compounds can enhance understanding of its structural formula.
Verified against NCERT Class XI Chemistry, Chapter 6 (General Principles and Processes of Isolation of Elements).
The intermixing of particles of two different types of matter on their own is called:
Diffusion is described by Fick's laws, which state that particles move from areas of higher concentration to areas of lower concentration until a uniform distribution is achieved.
When two substances are in contact, their molecules spontaneously move to achieve equilibrium. The fundamental principle can be summarized in the following reactions:
For example, consider the mixing of food coloring in water. The color disperses throughout the water as each dye particle moves from a region of high concentration (the drop) to lower concentrations (the surrounding water). This continues until a homogenous color is achieved.
Remember: "Diffuse the confusion" to recall that diffusion indicates the natural mixing of substances.
Illustrate diffusion using a diagram that shows particles dispersing from a concentrated area into a less concentrated environment, visually depicting the movement towards equilibrium.
Verified against NCERT Class XII Chemistry, Chapter on Physical Processes.
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