Please select a subject first
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Ozone is a/an _______ molecule and the two O-O bond lengths in ozone are (i) _______-and (ii) _________.
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Given below are two statements labelled as Assertion (A) and Reason (R).
Assertion (A): Cryoscopic constant depends on nature of solvent.
Reason (R): Cryoscopic constant is a universal constant.
Select the most appropriate answer from the options given below:
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Which of the following statements is false?
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How does sprinkling of salt help in clearing the snow covered roads in hilly areas? Explain the phenomenon involved in the process.
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Assertion: When NaCl is added to water a depression in freezing point is observed.
Reason: The lowering of vapour pressure of a solution causes depression in the freezing point.
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What advantage do the fuel cells have over primary and secondary batteries?
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Match the items of Column I and Column II.
| Column I | Column II |
| (i) Lead storage battery | (a) maximum efficiency |
| (ii) Mercury cell | (b) prevented by galvanisation |
| (iii) Fuel cell | (c) gives steady potential |
| (iv) Rusting | (d) Pb is anode, PbO2 is cathode |
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Which of the following interface cannot be obtained?
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Method by which lyophobic sol can be protected?
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Which of the following colloids cannot be coagulated easily?
(i) Lyophobic colloids.
(ii) Irreversible colloids.
(iii) Reversible colloids.
(iv) Lyophilic colloids.
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What happens when gelatin is mixed with gold sol?
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Match the items given in Column I and Column II.
| Column I | Column II |
| (i) Protective colloid | (a) \[\ce{FeCl3 + NaOH}\] |
| (ii) Liquid-liquid colloid | (b) Lyophilic colloids |
| (iii) Positively charged colloid | (c) Emulsion |
| (iv) Negatively charged colloid | (d) \[\ce{FeCl3}\] + hot water |
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A number of elements are available in earth’s crust but most abundant elements are ______.
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Explain why ozone is thermodynamically less stable than oxygen.
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Coagulation of egg white on boiling is an example of denaturation of protein. Explain it in terms of structural changes.
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Read the passage carefully and answer the questions that follow:
| Henna is investigating the melting point of different salt solutions. She makes a salt solution using 10 mL of water with a known mass of NaCl salt. She puts the salt solution into a freezer and leaves it to freeze. She takes the frozen salt solution out of the freezer and measures the temperature when the frozen salt solution melts. She repeats each experiment. |
| S.No | Mass of the salt used in g |
Melting point in °C | |
| Readings Set 1 | Reading Set 2 | ||
| 1 | 0.3 | -1.9 | -1.9 |
| 2 | 0.4 | -2.5 | -2.6 |
| 3 | 0.5 | -3.0 | -5.5 |
| 4 | 0.6 | -3.8 | -3.8 |
| 5 | 0.8 | -5.1 | -5.0 |
| 6 | 1.0 | -6.4 | -6.3 |
Assuming the melting point of pure water as 0°C, answer the following questions:
- One temperature in the second set of results does not fit the pattern. Which temperature is that? Justify your answer.
- Why did Henna collect two sets of results?
- In place of NaCl, if Henna had used glucose, what would have been the melting point of the solution with 0.6 g glucose in it?
OR
What is the predicted melting point if 1.2 g of salt is added to 10 mL of water? Justify your answer.
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Differentiate between the following:
Lyophobic Sol and Lyophilic Sol
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Which of the following cell was used in the Apollo space programme?
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When 25.6 g of sulphur was dissolved in 1000 g of benzene, the freezing point lowered by 0.512 K. Calculate the formula of sulphur (Sr).
(Kf for benzene = 5.12 K kg mol−1, Atomic mass of sulphur = 32 g mol−1)
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Out of the following 1.0 M aqueous solution, which one will show the largest freezing point depression?
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