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 581-590 of 1900 questions.
A. क्रिस्टल में जल के दस अणुTen water molecules in the crystal
Decahydrate means ten molecules of water.
Washing soda contains sodium carbonate with water of crystallisation.
Such numbers in hydrated salts are important for exams.
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Why does adding washing soda to hard water help in washing?
B. यह कैल्शियम और मैग्नीशियम आयनों को हटाने में सहायता करता हैIt helps remove calcium and magnesium ions
Hard water contains calcium and magnesium salts.
Washing soda helps remove these ions and softens water.
Soap forms better lather in soft water.
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Why does the blue colour return when water is added to white copper sulphate?
C. क्योंकि क्रिस्टलीय जल फिर जुड़ जाता हैBecause water of crystallisation is regained
White copper sulphate lacks water of crystallisation.
When water is added, it regains water of crystallisation and the blue colour returns.
This is a good experimental proof of water of crystallisation.
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Which statement about water of crystallisation is correct?
B. यह लवण क्रिस्टल में निश्चित अनुपात में उपस्थित जल होता हैIt is water present in a fixed ratio in salt crystals
In some salts, water is attached in a fixed ratio within crystals.
This water is called water of crystallisation.
It can affect the colour and shape of crystals.
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Which substance is formed when gypsum is heated at about 373 K?
C. प्लास्टर ऑफ पेरिसPlaster of Paris
Gypsum is a hydrated salt of calcium sulphate.
On controlled heating, it loses some water of crystallisation and forms plaster of Paris.
Temperature control is important in this preparation.
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Why is plaster of Paris stored away from moisture?
D. क्योंकि नमी पाकर यह धीरे-धीरे जम सकता हैBecause it can gradually set on absorbing moisture
Plaster of Paris reacts with water and becomes hard.
If it absorbs moisture, it may set before use.
Therefore, it is stored in a dry place in a closed container.
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On what can the pH of a salt depend?
C. जिस अम्ल और क्षार से वह बना है उनकी प्रकृति परOn the nature of the acid and base from which it is formed
Not every salt solution is neutral.
The nature of a salt can depend on the acid and base from which it is formed.
Understand combinations of strong and weak acids and bases separately.
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Why is an aqueous solution of sodium chloride nearly neutral?
A. क्योंकि यह प्रबल अम्ल और प्रबल क्षार से बना लवण हैBecause it is a salt of a strong acid and a strong base
Sodium chloride is formed from hydrochloric acid and sodium hydroxide.
Both are strong, so its solution is nearly neutral.
Such salts usually have pH close to 7.
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What is the usual nature of an aqueous solution of ammonium chloride?
C. अम्लीयAcidic
Ammonium chloride is considered a salt of a strong acid and a weak base.
Its aqueous solution shows acidic nature.
Relate the nature of salts to their parent acid and base.
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What is the usual nature of an aqueous solution of sodium carbonate?
C. क्षारीयBasic
Sodium carbonate is a salt of a weak acid and a strong base.
Its aqueous solution is basic in nature.
The basic nature of washing soda is related to its uses.
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