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प्रश्न
The teacher instructed three students ‘A’, ‘B’ and ‘C’ respectively to prepare a 50% (mass by volume) solution of sodium hydroxide (NaOH). ‘A’ dissolved 50g of NaOH in 100 mL of water, ‘B’ dissolved 50g of NaOH in 100g of water while ‘C’ dissolved 50g of NaOH in water to make 100 mL of solution. Which one of them has made the desired solution and why?
उत्तर
By definition, 50% mass by volume percent solution means 50 grams of a solute dissolved in 100 mL of solution. Therefore, student C made the desired solution. Student A dissolved 50 g of NaOH in 100 ml of water, So the solution is diluted and is not the desired solution. By definition, 50% mass by mass percent solution means 50 grams of a solute dissolved in 100 grams of solution.
Student B dissolved 50 g of NaOH in 150 g of the solution so, it is not the desired solution.
‘C’ has made the desired solution by dissolving 50 g NaOH in water to make the volume of the solution 100 mL
Mass by volume % = `("Mass of solute")/("Volume of solution") xx 100`
= `50/100 xx 100`
= 50% mass by volume
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संबंधित प्रश्न
Pragya tested the solubility of three different substances at different temperatures and collected the data as given below (results are given in the following table, as grams of substance dissolved in 100 grams of water to form a saturated solution).
| Substance dissolved | Temperature in K | ||||
| 283 | 293 | 313 | 333 | 353 | |
| Solubility | |||||
| Potassium nitrate | 21 | 32 | 62 | 106 | 167 |
| Sodium chloride | 36 | 36 | 36 | 37 | 37 |
| Potassium chloride | 35 | 35 | 40 | 46 | 54 |
| Ammonium chloride | 24 | 37 | 41 | 55 | 66 |
- What mass of potassium nitrate would be needed to produce a saturated solution of potassium nitrate in 50 grams of water at 313 K?
- Pragya makes a saturated solution of potassium chloride in water at 353 K and leaves the solution to cool at room temperature. What would she observe as the solution cools? Explain.
- Find the solubility of each salt at 293 K. What salt has the highest solubility at this temperature?
- What is the effect of change of temperature on the solubility of a salt?
Identify the solutions among the following mixtures.
- Soil
- Sea water
- Air
- Coal
- Soda water
The number of components in a binary solution is ______
The component present in a lesser amount, in a solution, is called ______
Give an example of gas in a liquid.
Give an example of a solid in a liquid.
Smoke and fog both are aerosols. In what way are they different?
A solution is always a liquid. Comment.
A group of students took an old shoebox and covered it with black paper from all sides. They fixed a source of light (a torch) at one end of the box by making a hole in it and making another hole on the other side to view the light. They placed a milk sample contained in a beaker/tumbler in the box as shown in Fig.2.4. They were amazed to see that milk taken in the tumbler was illuminated. They tried the same activity by taking a salt solution but found that light simply passed through it?
(a) Explain why the milk sample was illuminated. Name the phenomenon involved.
(b) The same results were not observed with a salt solution. Explain.
(c) Can you suggest two more solutions that would show the same effect as shown by the milk solution?
Arun has prepared a 0.01% (by mass) solution of sodium chloride in water. Which of the following correctly represents the composition of the solutions?
