21187.The mass of carbon anode consumed (giving only carbon dioxide) in the production of 270 kg of aluminium metal from bauxite by the Hall process is: (Atomic mass : Al = 27)
90 kg
540 kg
180 kg
270 kg
21188.The number of water molecules is maximum in
18 gram of water
18 moles of water
18 molecules of water
1.8 gram of water
21189.1.78 g of an optically active L-amino acid is treated with NaNO2/HCl at 0º C. 448 cm3 of nitrogen was at STP is evolved. A sample of protein has 0.25% of this amino acid by mass. The molar mass of the protein is
36,500 g mol-1
34,500 g mol-1
35,400 g mol-1
35,600 g mol-1
21190.The system that contains the maximum number of atoms is
4.25 g of NH3
8 g of O2
2 g of H2
4 g of He
21191.20.0 g of a magnesium carbonate sample decomposes on heating to give carbon dioxide and 8.0 g magnesium oxide. What will be the percentage purity of magnesium carbonate in the sample? (At. wt. : Mg = 24)
60
84
75
96
21192.How many moles of lead (II) chloride will be formed from a reaction between 6.5 g of PbO and 3.2 g of HCl?
0.044
0.333
0.011
0.029
21193.Suppose the elements X and Y combine to form two compounds XY2 and X3Y2. When 0.1 mole of XY2 weighs 10 g and 0.05 mole of X3Y2 weighs 9 g, the atomic weights of X and Y are
40, 30
60, 40
20, 30
30, 20
21194.10 g of a mixture of BaO and CaO requires 100 cm3 of 2.5 M HCl to react completely. The percentage of calcium oxide in the mixture is approximately (Given : molar mass of BaO = 153)
52.6
55.1
44.9
47.4
21195.10 g of hydrogen and 64 g of oxygen were filled in a steel vessel and exploded. Amount of water produced in this reaction will be
1 mol
2 mol
3 mol
4 mol
21196.KMnO4 reacts with KI in basic medium to form I2 and MnO2. When 250 mL of 0.1 M KI solution is mixed with 250 mL of 0.02 M KMnO4 in basic medium, what is the number of moles of I2 formed?
0.0075
0.005
0.01
0.015
21197.50 cm3 of 0.04 M K2Cr2O7 in acidic medium oxidizes a sample of H2S gas to sulphur. Volume of 0.03 M KMnO4 required to oxidize the same amount of H2S gas to sulphur, in acidic medium is
60 cm3
80 cm3
90 cm3
120 cm3
21198.Volume occupied by one molecule of water (density = 1 g cm–3) is
9.0 × 10–23 cm3
6.023 × 10–23 cm3
3.0 × 10–23 cm3
5.5 × 10–23 cm3
21199.Number of moles of MnO–
4 required to oxidize one mole of ferrous oxalate completely in acidic medium will be
4 required to oxidize one mole of ferrous oxalate completely in acidic medium will be
0.6 moles
0.4 moles
7.5 moles
0.2 moles
21200.The molarity of a solution obtained by mixing 750 mL of 0.5(M) HCl with 250 mL of 2(M) HCl will be :
0.875 M
1.00 M
1.75 M
0.975 M
21201.The number of moles of KMnO4 that will be needed to react with one mole of sulphite ion in acidic solution is:
1
3/5
4/5
2/5