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What is an Aqueous Solution (water solvent)?
Grade Level:
Class 7
Space Technology, EVs, Climate Change, Biotechnology, HealthTech, Robotics, Chemistry, Physics
Definition
What is it?
An aqueous solution is a special type of mixture where a substance is completely dissolved in water. In these solutions, water acts as the 'dissolver' or solvent, and the substance dissolved in it is called the solute.
Simple Example
Quick Example
Imagine you're making nimbu paani (lemonade) at home. You take a glass of water and add a spoonful of sugar. You stir it, and the sugar disappears, mixing completely with the water. This sugar-water mixture is an aqueous solution.
Worked Example
Step-by-Step
Let's say you want to make a salt solution for an experiment.
1. Take a clean glass.
2. Pour 100 ml of clean drinking water into the glass. This is your solvent.
3. Add 5 grams of common table salt (sodium chloride) into the water. This is your solute.
4. Stir the mixture well with a spoon until all the salt crystals disappear and the water looks clear again.
5. You now have an aqueous solution of salt water.
Why It Matters
Understanding aqueous solutions is crucial in fields like Biotechnology, where scientists create medicines dissolved in water, or in HealthTech, for making saline solutions used in hospitals. Even in Climate Change research, studying how pollutants dissolve in rainwater involves aqueous solutions, helping us find ways to keep our environment clean.
Common Mistakes
MISTAKE: Thinking that any liquid mixture is an aqueous solution. | CORRECTION: An aqueous solution specifically means water is the solvent. If you dissolve sugar in oil, it's a solution, but not an aqueous one.
MISTAKE: Believing that 'dissolving' means the substance disappears completely and cannot be recovered. | CORRECTION: While the solute spreads evenly, it's still present. You can often recover the solute by evaporating the water, like getting salt back from salt water.
MISTAKE: Confusing a suspension or colloid with an aqueous solution. | CORRECTION: In an aqueous solution, the solute particles are very tiny and spread evenly, making the solution transparent. In suspensions (like mud in water), particles settle, and in colloids (like milk), particles are larger and scatter light.
Practice Questions
Try It Yourself
QUESTION: Is a mixture of sand and water an aqueous solution? | ANSWER: No, because sand does not dissolve in water; it settles at the bottom.
QUESTION: You add a pinch of turmeric powder to a glass of water and stir. Does it form an aqueous solution? Explain. | ANSWER: No, it forms a suspension because turmeric powder does not fully dissolve in water; it remains as fine particles.
QUESTION: Your mother makes a cup of coffee by adding coffee powder and sugar to hot water. Identify the solvent and the solutes in this mixture. Is it an aqueous solution? | ANSWER: The solvent is hot water. The solutes are coffee powder and sugar. Yes, it is an aqueous solution because water is the solvent.
MCQ
Quick Quiz
Which of the following is an example of an aqueous solution?
Oil mixed with water
Salt dissolved in water
Sand mixed with water
Milk
The Correct Answer Is:
B
Option B is correct because salt completely dissolves in water, forming a clear mixture where water is the solvent. Oil and sand do not dissolve in water, and milk is a colloid, not a true solution.
Real World Connection
In the Real World
When you get an injection at the doctor's clinic, the medicine is often dissolved in water, forming an aqueous solution, making it easy for your body to absorb. Many packaged juices and soft drinks you buy also contain sugar, flavors, and colors dissolved in water, making them aqueous solutions.
Key Vocabulary
Key Terms
SOLVENT: The substance that dissolves another substance, usually present in a larger amount. | SOLUTE: The substance that gets dissolved in the solvent, usually present in a smaller amount. | SOLUTION: A homogeneous mixture formed when a solute dissolves in a solvent. | DISSOLVE: To mix completely with a liquid to form a solution.
What's Next
What to Learn Next
Now that you understand aqueous solutions, you can explore concepts like 'Solubility' to learn how much of a substance can dissolve in water, and 'Factors Affecting Solubility' to see how temperature and stirring change this process. Keep up the great work!
