19,000+ solved questions for JEE Advanced, JEE Mains, NEET & IChO — with answers and expert explanations.
20.0 kg of N2(g) and 3.0 kg of H2(g) are mixed to produce NH3 (g). The amount of NH3(g) formed is (Kerala CEE 2011)
60g of a compound on analysis produced 24g of carbon, 4g hydrogen and 32g oxygen. The empirical formula of the compound is. (BVP 2010)
The number of atoms in 0.1 mol of a triatomic gas is ( A N =6.022×10 ) (CBSE AIPMT 2010)
The result of the operation 2.5 × 1.5 should be which of the following on the basis of significant figures?
A mixture of CaCl2 and NaCl weighing 4.44 g is treated with sodium carbonate to precipitate all the Ca2+ ions as calcium carbonate. The calcium carbonate so obtained is heated strongly to get 0.56 g of CaO. The percen…
Volume of a gas at NTP is 1.12×10–7 cm3. The number of molecules in it is (Manipal 2010)
If 1 mL of water contains 20 drops the number of molecules in a drop of water is (AFMC 2010)
74.5 g of a metallic chloride contain 35.5 g of chlorine. The equivalent weight of the metal is (Manipal 2010)
2.005 has ….A…. significant figures. Here, A refers to
The ore having two different metal atoms is (AIPMT 2006)
Assertion: All the ores are mineral. Reason: Ores contains metals in combined state
Assertion: Al2O3 is converted into Al by reduction with carbon at high temp. Reason: Carbon has greater affinity for oxygen than aluminium.
Assertion: Lead, tin and bismuth are purified by liquation method. Reason: Lead, tin and bismuth have low m.p. as compared to impurities.
Assertion: Wrought iron is more malleable and ductile than steel. Reason: It contains slightly less percentage of carbon.
Assertion: In the electrolytic reduction of Al2O3, cryolite is used. Reason: Cryolite is an ore of aluminium.
Assertion: CuFeS2 is concentrated by froth floatation method. Reason: CuFeS2 is main ore of copper.
Refining of impure copper with zinc impurity is to be done by electrolysis using electrodes as Cathode Anode
The methods chiefly used for the extraction of lead and tin from their ores are respective
Consider the following metallurgical processes: (I) Heating impure metal with CO and distilling the resulting volatile carbonyl (b.p. 430C) and finally decomposition at 1500-2000C to get the pure metal (II) Heating th…
Which of the following pair of ores cannot be converted into corresponding metals by pyrometallurgy?
Formation of metallic copper from the sulphide ore in the commercial metallurgical process involves. (a) Cu S+ O Cu O+SO ; Cu O+C 2Cu+CO -> -> (b) Cu S O Cu O SO ; 2Cu O Cu S 6Cu SO -> -> (c) Cu S 2O CuSO ; CuSO C…
Which of the following factors is of no significance for roasting sulphide ores to the oxides and not subjecting the sulphide ores to carbon reduction directly
Select correct statement:
Boron can be obtained by various methods but not by:
Among the following statements, the incorrect one is: