Practice focused topic-wise MCQs with answers and explanations for quick revision and exam preparation.
Difficulty select karke sirf is topic ke focused MCQs practice karein. Score, timer aur explanations student-friendly flow me milenge.
Showing 531-540 of 1900 questions.
What is one major use of washing soda?
A. जल की स्थायी कठोरता दूर करनाRemoving permanent hardness of water
Hard water contains calcium and magnesium salts.
Washing soda helps remove these ions.
Therefore, it is used to soften hard water.
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What does water of crystallisation mean?
A. लवण में उपस्थित निश्चित मात्रा का जलFixed amount of water present in a salt crystal
Some salt crystals contain a fixed amount of water.
This water is called water of crystallisation.
It can affect the shape and colour of crystals.
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Why do blue copper sulphate crystals turn white on heating?
B. क्योंकि क्रिस्टलीय जल निकल जाता हैBecause water of crystallisation is lost
Blue copper sulphate contains water of crystallisation.
On heating, this water is lost and the substance turns white.
Adding water can restore the blue colour.
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From which substance is plaster of Paris prepared?
A. जिप्सम को गरम करकेBy heating gypsum
Gypsum is a hydrated form of calcium sulphate.
Plaster of Paris is prepared by heating gypsum at a controlled temperature.
Controlled heating is important because overheating changes its properties.
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Why is plaster of Paris used for making casts on fractured bones?
A. यह जल मिलाने पर जल्दी कठोर हो जाता हैIt sets hard quickly on adding water
Plaster of Paris forms a hard gypsum-like substance when mixed with water.
It sets quickly and helps keep the fractured bone stable.
Link its setting property with its medical use.
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Which of the following is an example of a strong acid?
A. हाइड्रोक्लोरिक अम्लHydrochloric acid
Strong acids ionise almost completely in water.
Hydrochloric acid is a strong acid.
Acetic acid is a common example of a weak acid.
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Which of the following is an example of a weak acid?
D. सिरके का अम्लAcetic acid
Weak acids ionise only partially in water.
Acetic acid is a weak acid.
Distinguish strong and weak acids on the basis of ionisation.
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What is the main basis of difference between concentrated acid and dilute acid?
A. अम्ल की मात्रा प्रति विलयनAmount of acid per solution
Concentration tells how much acid is present in a solution.
Concentrated acid has more acid, while dilute acid has less acid.
Do not confuse strength with concentration.
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What happens to the temperature of the solution when acid is mixed with water?
B. तापमान बढ़ता हैTemperature increases
Dissolving acid in water releases heat.
The released heat raises the temperature of the solution.
This is why acid is added slowly to water.
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Why does dry hydrogen chloride gas not change the colour of dry litmus paper?
A. क्योंकि जल की अनुपस्थिति में आयन नहीं बनतेBecause ions are not formed in the absence of water
Water is needed for acids to show acidic behaviour.
In dry conditions, hydrogen ions are not produced, so dry litmus does not change.
Moist litmus can show the colour change.
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