List any two observations when a highly reactive metal is dropped in water.
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An object is dropped from rest at a height of 150 m and simultaneously another object is dropped from rest at a height 100 m.
Initial difference in height = (150 – 100) m = 50 m Distance travelled by first body in 2 s = h1 = 0 + 1/ 2 g (2)2 = 2...
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Water as ice has a cooling effect, whereas water as steam may cause severe burns. Explain these observations.
In case of ice the water molecules have low energy while in the case of steam the water molecules have high energy. The high energy of water molecules in steam...
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Can a double displacement reaction take place when the products are highly soluble or highly ionised?
No, double displacement reaction takes place when there is a formation of a slightly soluble salt.
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Give reasons: Aluminium is a highly reactive metal, yet it is used to make utensils for cooking.
Aluminium metal forms a thin layer of aluminium oxide all over its surface under the action of moist air. This layer prevents the metal underneath from further corrosion. It is...
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During the experiment of heating of ferrous sulphate crystals, four students recorded their observations as:observations as:
(B) (i), (iv)
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The reaction of a metal ‘X’ with Fe2O3 is highly exothermic and is used to join broken railway tracks. Identify metal ‘X’.
Metal X is Aluminium Fe2O3 + 2Al → 2Fe + Al2O3 + heat Thermite reaction
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Electronegativity of oxygen is more than sulphur yet H2S is acidic while water is neutral. This is because (a) water is highly associated compound
(d) SH–bond is weaker than, O–H bond. Hence H2 S will furnish more H+ ions
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Match List-I with List-II and select the correct answer using the codes given below the lists: List-I (Year) List-II (Event)
(c) First Anglo-Burmese War – Burmese defeated, Treaty of Yandobo (1826); First Anglo-Afghan War – Afghan defeated (1838); First Anglo-Maratha War – Britishers were defeated, Treaty of Salbai (1782); Second...
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When a cation is highly polarizing? Which alkali metal cation has the highest polarizing power?
A cation is highly polarizing if its charge/size ratio is very high.Li+ has the highest polarizing power.
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What happens when (i) Sodium metal is dropped in water ? (ii) Sodium metal is heated in free supply of air ?
(I) 2 Na(s) + 2 H2O------> 2NaOH + H2 (II) Na2O2 is formed 2 Na + O2 ------> Na2O2 (iii) H2O2 is formed Na2O2 + 2 H2O------> 2 NaOH + H2O2
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